Adipose tissue dysfunction signals progression of hepatic steatosis towards nonalcoholic steatohepatitis in C57BL/6 mice

Role and therapeutic perspectives of extracellular vesicles derived from liver and adipose tissue in metabolic dysfunction-associated steatotic liver disease

The global epidemic of metabolic diseases has led to the emergence of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH), which pose a significant threat to human health. Despite recent advances in research on the pathogenesis and treatment of MASLD/MASH, there is still a lack of more effective and targeted therapies. Extracellular vesicles (EVs) discovered in a wide range of tissues and body fluids encapsulate different activated biomolecules and mediate intercellular communication. Recent studies have shown that EVs derived from the liver and adipose tissue (AT) play vital roles in MASLD/MASH pathogenesis and therapeutics, depending on their sources and intervention types. Besides, adipose-derived stem cell (ADSC)-derived EVs appear to be more effective in mitigating MASLD/MASH. This review presents an overview of the definition, extraction strategies, and characterisation of EVs, with a particular focus on the biogenesis and release of exosomes. It also reviews the effects and potential molecular mechanisms of liver- and AT-derived EVs on MASLD/MASH, and emphasises the contribution and clinical therapeutic potential of ADSC-derived EVs. Furthermore, the future perspective of EV therapy in a clinical setting is discussed.

TRIM24 Up-Regulates ORM2 to Alleviate Abnormal Lipid Metabolism, Inflammation, and Oxidative Stress in Mice with Obstructive Sleep Apnea Syndrome and Metabolic Dysfunction-Associated Steatotic Liver Disease

Obstructive sleep apnea syndrome (OSAS) is associated with the development and progression of metabolic dysfunction-associated steatotic liver disease (MASLD). Tripartite motif containing 24 (TRIM24) deficiency was reported to cause hepatic lipid accumulation and hepatitis. However, the expression, function, and mechanism of TRIM24 in OSAS and MASLD remain unclear. OSAS and MASLD mouse model was established by intermittent hypoxia (IH) and high-fat diet. IH- and 1% free fatty acid-induced mouse liver cells served as an in vitro model. TRIM24 and HIF-1α were up-regulated under the IH condition. HIF-1α enhanced the transcriptional activity of TRIM24. Overexpression of TRIM24 reduced hepatic lipid accumulation, decreased serum levels of total cholesterol, triglyceride, and low-density lipoprotein cholesterol, and increased serum levels of high-density lipoprotein cholesterol in OSAS and MASLD mice. Additionally, overexpression of TRIM24 alleviated inflammation and oxidative stress, and modulated aberrant lipid metabolism. Mechanically, TRIM24 up-regulated the expression of ORM2, a key regulator of hepatic lipogenesis, by binding to H3K27ac and recruiting retinoic acid receptor-α to ORM2 promoter. The cell rescue model verified that ORM2 mediated the hepatoprotective effects of TRIM24. Our evidence reveals the important role of TRIM24 as an epigenetic coregulator of transcription in OSAS and MASLD, providing additional insights into understanding the pathogenesis and preventing the development of OSAS and MASLD.

Unravelling the complexities of non-alcoholic steatohepatitis: The role of metabolism, transporters, and herb-drug interactions

Nonalcoholic fatty liver disease (NAFLD) is a mainstream halting liver disease with high prevalence in North America, Europe, and other world regions. It is an advanced form of NAFLD caused by the amassing of fat in the liver and can progress to the more severe form known as non-alcoholic steatohepatitis (NASH). Until recently, there was no authorized pharmacotherapy reported for NASH, and to improve the patient's metabolic syndrome, the focus is mainly on lifestyle modification, weight loss, ensuring a healthy diet, and increased physical activity; however, the recent approval of Rezdiffra (Resmetirom) by the US FDA may change this narrative. As per the reported studies, there is an increased articulation of uptake and efflux transporters of the liver, including OATP and MRP, in NASH, leading to changes in the drug's pharmacokinetic properties. This increase leads to alterations in the pharmacokinetic properties of drugs. Furthermore, modifications in Cytochrome P450 (CYP) enzymes can have a significant impact on these properties. Xenobiotics are metabolized primarily in the liver and constitute liver enzymes and transporters. This review aims to delve into the role of metabolism, transport, and potential herb-drug interactions in the context of NASH.

The Emerging Role of Glucagon-Like Peptide-1 Receptor Agonists for the Treatment of Metabolic Dysfunction-Associated Steatohepatitis

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects 1 in 3-4 adult individuals and can progress to metabolic dysfunction-associated steatohepatitis (MASH) and cirrhosis. Insulin resistance plays a central role in MASLD/MASH pathophysiology with higher rates of MASLD (2 in 3) and MASH with fibrosis (1 in 5) in adults with obesity and diabetes. This review summarizes the role of glucagon-like peptide-1 receptor agonists in treating MASLD/MASH. Although not approved by the Food and Drug Administration for the treatment of MASLD, this class of medication is available to treat obesity and type 2 diabetes and has been shown to reverse steatohepatitis, reduce cardiovascular risk, and is safe to use across the spectrum of MASLD with or without fibrosis.

miR-155-5p promotes hepatic steatosis via PICALM-mediated autophagy in aging hepatocytes

BACKGROUND

Hepatic steatosis, a lipid disorder characterized by the accumulation of intrahepatic fat, is more prevalent in the elderly population. This study investigates the role of miR-155-5p in the autophagy dysregulation of aging hepatic steatosis.

METHODS

We established an aging mouse model in vivo and a hepatocellular senescence model induced by low serum and palmitic acid in vitro. The fluctuations of microRNAs were derived from RNA-seq data and confirmed by qPCR in 4- and 18-month-old mouse liver tissues. Hematoxylin-eosin (H&E) staining observed pathological changes. Markers of senescence, autophagy, and lipolysis genes were analyzed using Western blot and qPCR. Bioinformatics analysis predicted miR-155-5p's target gene PICALM, confirmed by dual luciferase reporter assay and transfection of miR-155-5p mimic/inhibitor into senescent hepatocytes.

RESULTS

Senescent markers (p21, p16, and p-P53) and miR-155-5p were up-regulated in aging liver tissues and senescent hepatocytes. Bioinformatics analysis identified PICALM as a target gene of miR-155-5p, a finding further supported by dual luciferase reporter assays. Inhibition of miR-155-5p reduced expression of senescent marker genes (p16, p21, p-P53), improved autophagy (evidenced by increased LC3B-II and ATG5, and decreased P62), and enhanced lipolysis (indicated by increased ATGL and p-HSL) in senescent hepatocytes. Oil red O staining confirmed that miR-155-5p inhibition significantly reduced lipid accumulation in these cells.

CONCLUSIONS

This study suggests a potential new therapeutic approach for age-related hepatic steatosis through the inhibition of miR-155-5p to enhance autophagy.

Coagulation Factor VII Fine-tunes Hepatic Steatosis by Blocking AKT-CD36-Mediated Fatty Acid Uptake

Nonalcoholic fatty liver disease (NAFLD) is considered a risk factor for cardiovascular and cerebrovascular disease owing to its close association with coagulant disturbances. However, the precise biological functions and mechanisms that connect coagulation factors to NAFLD pathology remain inadequately understood. Herein, with unbiased bioinformatics analyses followed by functional testing, we demonstrate that hepatic expression of coagulation factor VII (FVII) decreases in patients and mice with NAFLD/nonalcoholic steatohepatitis (NASH). By using adenovirus-mediated F7-knockdown and hepatocyte-specific F7-knockout mouse models, our mechanistic investigations unveil a noncoagulant function of hepatic FVII in mitigating lipid accumulation and lipotoxicity. This protective effect is achieved through the suppression of fatty acid uptake, orchestrated via the AKT-CD36 pathway. Interestingly, intracellular FVII directly interacts with AKT and PP2A, thereby promoting their association and triggering the dephosphorylation of AKT. Therapeutic intervention through adenovirus-mediated liver-specific overexpression of F7 results in noteworthy improvements in liver steatosis, inflammation, injury, and fibrosis in severely afflicted NAFLD mice. In conclusion, our findings highlight coagulation factor FVII as a critical regulator of hepatic steatosis and a potential target for the treatment of NAFLD and NASH.

ARTICLE HIGHLIGHTS

Emerging Insights into the Role of BDNF on Health and Disease in Periphery

Brain-derived neurotrophic factor (BDNF) is a growth factor that promotes the survival and growth of developing neurons. It also enhances circuit formation to synaptic transmission for mature neurons in the brain. However, reduced BDNF expression and single nucleotide polymorphisms (SNP) are reported to be associated with functional deficit and disease development in the brain, suggesting that BDNF is a crucial molecule for brain health. Interestingly, BDNF is also expressed in the hypothalamus in appetite and energy metabolism. Previous reports demonstrated that BDNF knockout mice exhibited overeating and obesity phenotypes remarkably. Therefore, we could raise a hypothesis that the loss of function of BDNF may be associated with metabolic syndrome and peripheral diseases. In this review, we describe our recent finding that BDNF knockout mice develop metabolic dysfunction-associated steatohepatitis and recent reports demonstrating the role of one of the BDNF receptors, TrkB-T1, in some peripheral organ functions and diseases, and would provide an insight into the role of BDNF beyond the brain.

Brain-derived neurotrophic factor knock-out mice develop non-alcoholic steatohepatitis

While brain-derived neurotrophic factor (BDNF), which is a growth factor associated with cognitive improvement and the alleviation of depression symptoms, is known to regulate food intake and body weight, the role of BDNF in peripheral disease is not fully understood. Here, we show that reduced BDNF expression is associated with weight gain and the chronic liver disease non-alcoholic steatohepatitis (NASH). At 10 months of age, BDNF-heterozygous (BDNF+/- ) mice developed symptoms of NASH: centrilobular/perivenular steatosis, lobular inflammation with infiltration of neutrophils, ballooning hepatocytes, and fibrosis of the liver. Obesity and higher serum levels of glucose and insulin - major pathologic features in human NASH - were dramatic. Dying adipocytes were surrounded by macrophages in visceral fat, suggesting that chronic inflammation occurs in peripheral organs. RNA sequencing (RNA-seq) studies of the liver revealed that the most significantly enriched Gene Ontology term involved fatty acid metabolic processes and the modulation of neutrophil aggregation, pathologies that well characterise NASH. Gene expression analysis by RNA-seq also support the notion that BDNF+/- mice are under oxidative stress, as indicated by alterations in the expression of the cytochrome P450 family and a reduction in glutathione S-transferase p, an antioxidant enzyme. Histopathologic phenotypes of NASH were also observed in a knock-in mouse (BDNF+/pro ), in which the precursor BDNF is inefficiently converted into the mature form of BDNF. Lastly, as BDNF reduction causes overeating and subsequent obesity, a food restriction study was conducted in BDNF+/pro mice. Pair-fed BDNF+/pro mice developed hepatocellular damage and showed infiltration of inflammatory cells, including neutrophils in the liver, despite having body weights and blood parameters that were comparable to those of controls. This is the first report demonstrating that reduced BDNF expression plays a role in the pathogenic mechanism of NASH, which is a hepatic manifestation of metabolic syndrome. © 2023 The Pathological Society of Great Britain and Ireland.

Non-alcoholic fatty liver disease in women - Current knowledge and emerging concepts

Non-alcoholic fatty liver disease (NAFLD) is a major cause of liver disease worldwide, affecting up to 30% of adults. Progression to non-alcoholic steatohepatitis (NASH) is a key risk factor for cirrhosis, hepatocellular carcinoma and cardiovascular events. Alterations in reproductive hormones are linked to the development and/or progression of NAFLD/NASH in women. Women with polycystic ovary syndrome and those with oestrogen deficiency are at increased risk of NAFLD/NASH, with higher mortality rates in older women compared to men of similar ages. NAFLD/NASH is currently the leading indication for liver transplantation in women without hepatocellular carcinoma. Therefore, a better understanding of NAFLD in women is needed to improve outcomes. In this review, we discuss the hormonal and non-hormonal factors that contribute to NAFLD development and progression in women. Furthermore, we highlight areas of focus for clinical practice and for future research.

Combined with multiplex and network analysis to reveal the key genes and mechanisms of nonalcoholic fatty liver disease

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) has become a significant cause of chronic liver disease in developed countries, as a result of the worldwide trend of obesity and associated metabolic syndrome. Obesity and high-fat diet (HFD) are very common in patients with NAFLD. However, how to screen out key differentially expressed genes (DEGs) is a challenging task. The purpose of this study is to study the screen of key genes and pathways of HFD on the formation process of non-alcoholic fatty liver through network pharmacological analysis.

METHODS

In this study, 173 genes associated with NAFLD were collected from the Gene Expression Omnibus (GEO) database. To find significant genes and pathways, combine network clustering analysis, topology analysis, and pathway analysis.

RESULTS

The results showed that there were four key signaling pathways related to HFD, including complement cascade, Atorvastatin ADME, Asthma and Aflatoxin activation and detoxification. In addition, we identified six representative key genes, including Ccl5, Tlr2, Cd274, Cxcl10, Cxcl9 and Cd74, and screened three intersecting genes in Mus musculus and Homo sapiens sample, including C3, F2 and C7.

CONCLUSIONS

In conclusion, our study constructed the NAFLD gene regulatory network of C57BL/6J mice for the first time and jointly analyzed the Mus musculus samples and Homo sapiens samples. It provides new insights for identifying potential biomarkers and valuable therapeutic clues, and puts forward a new method for web-based research. These findings may provide potential targets for early diagnosis, effective therapy and prognostic markers of NAFLD.

Conferring liver selectivity to a thyromimetic using a novel nanoparticle increases therapeutic efficacy in a diet-induced obesity animal model

Optimization of metabolic regulation is a promising solution for many pathologies, including obesity, dyslipidemia, type 2 diabetes, and inflammatory liver disease. Synthetic thyroid hormone mimics-based regulation of metabolic balance in the liver showed promise but was hampered by the low biocompatibility and harmful effects on the extrahepatic axis. In this work, we show that specifically directing the thyromimetic to the liver utilizing a nanogel-based carrier substantially increased therapeutic efficacy in a diet-induced obesity mouse model, evidenced by the near-complete reversal of body weight gain, liver weight and inflammation, and cholesterol levels with no alteration in the thyroxine (T4) / thyroid stimulating hormone (TSH) axis. Mechanistically, the drug acts by binding to thyroid hormone receptor β (TRβ), a ligand-inducible transcription factor that interacts with thyroid hormone response elements and modulates target gene expression. The reverse cholesterol transport (RCT) pathway is specifically implicated in the observed therapeutic effect. Overall, the study demonstrates a unique approach to restoring metabolic regulation impacting obesity and related metabolic dysfunctions.

Reduction of Obesity and Insulin Resistance through Dual Targeting of VAT and BAT by a Novel Combination of Metabolic Cofactors

Obesity is an epidemic disease worldwide, characterized by excessive fat accumulation associated with several metabolic perturbations, such as metabolic syndrome, insulin resistance, hypertension, and dyslipidemia. To improve this situation, a specific combination of metabolic cofactors (MC) (betaine, N-acetylcysteine, L-carnitine, and nicotinamide riboside) was assessed as a promising treatment in a high-fat diet (HFD) mouse model. Obese animals were distributed into two groups, orally treated with the vehicle (obese + vehicle) or with the combination of metabolic cofactors (obese + MC) for 4 weeks. Body and adipose depots weights; insulin and glucose tolerance tests; indirect calorimetry; and thermography assays were performed at the end of the intervention. Histological analysis of epidydimal white adipose tissue (EWAT) and brown adipose tissue (BAT) was carried out, and the expression of key genes involved in both fat depots was characterized by qPCR. We demonstrated that MC supplementation conferred a moderate reduction of obesity and adiposity, an improvement in serum glucose and lipid metabolic parameters, an important improvement in lipid oxidation, and a decrease in adipocyte hypertrophy. Moreover, MC-treated animals presented increased adipose gene expression in EWAT related to lipolysis and fatty acid oxidation. Furthermore, MC supplementation reduced glucose intolerance and insulin resistance, with an increased expression of the glucose transporter Glut4; and decreased fat accumulation in BAT, raising non-shivering thermogenesis. This treatment based on a specific combination of metabolic cofactors mitigates important pathophysiological characteristics of obesity, representing a promising clinical approach to this metabolic disease.

Dietary EPA+DHA Mitigate Hepatic Toxicity and Modify the Oxylipin Profile in an Animal Model of Colorectal Cancer Treated with Chemotherapy

Irinotecan (CPT-11) and 5-fluorouracil (5-FU) are commonly used to treat metastatic colorectal cancer, but chemotherapy-associated steatosis/steatohepatitis (CASSH) frequently accompanies their use. The objective of this study was to determine effect of CPT-11+5-FU on liver toxicity, liver oxylipins, and cytokines, and to explore whether these alterations could be modified by dietary eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the form of fish oil (EPA+DHA). Tumor-bearing animals were administered CPT-11+5-FU and maintained on a control diet or a diet containing EPA+DHA (2.3 g/100 g). Livers were collected one week after chemotherapy for the analysis of oxylipins, cytokines, and markers of liver pathology (oxidized glutathione, GSSH; 4-hydroxynonenal, 4-HNE, and type-I collagen fiber). Dietary EPA+DHA prevented the chemotherapy-induced increases in liver GSSH (p < 0.011) and 4-HNE (p < 0.006). Compared with the tumor-bearing animals, ten oxylipins were altered (three/ten n-6 oxylipins were elevated while seven/ten n-3 oxylipins were reduced) following chemotherapy. Reductions in the n-3 fatty-acid-derived oxylipins that were evident following chemotherapy were restored by dietary EPA+DHA. Liver TNF-α, IL-6 and IL-10 were elevated (p < 0.05) following chemotherapy; dietary EPA+DHA reduced IL-6 (p = 0.09) and eotaxin (p = 0.007) levels. Chemotherapy-induced liver injury results in distinct alterations in oxylipins and cytokines, and dietary EPA+DHA attenuates these pathophysiological effects.

Deletion of adipocyte prohibitin 1 exacerbates high-fat diet-induced steatosis but not liver inflammation and fibrosis

Adipose tissue dysfunction is closely associated with the development and progression of nonalcoholic fatty liver disease (NAFLD). Recent studies have implied an important role of prohibitin-1 (PHB1) in adipose tissue function. In the current study, we aimed to explore the function of adipocyte PHB1 in the development and progression of NAFLD. The PHB1 protein levels in adipose tissues were markedly decreased in mice fed a high-fat diet (HFD) compared to those fed a chow diet. To explore the function of adipocyte PHB1 in the progression of NAFLD, mice with adipocyte-specific (adipo) deletion of Phb1 (Phb1^adipo-/- mice) were generated. Notably, Phb1^adipo-/- mice did not develop obesity but displayed severe liver steatosis under HFD feeding. Compared to HFD-fed wild-type (WT) mice, HFD-fed Phb1^adipo-/- mice displayed dramatically lower fat mass with significantly decreased levels of total adipose tissue inflammation, including macrophage and neutrophil number as well as the expression of inflammatory mediators. To our surprise, although liver steatosis in Phb1^adipo-/- mice was much more severe, liver inflammation and fibrosis were similar to WT mice after HFD feeding. RNA sequencing analyses revealed that the interferon pathway was markedly suppressed while the bone morphogenetic protein 2 pathway was significantly up-regulated in the liver of HFD-fed Phb1^adipo-/- mice compared with HFD-fed WT mice. Conclusion: HFD-fed Phb1^adipo-/- mice display a subtype of the lean NAFLD phenotype with severe hepatic steatosis despite low adipose mass. This subtype of the lean NAFLD phenotype has similar inflammation and fibrosis as obese NAFLD in HFD-fed WT mice; this is partially due to reduced total adipose tissue inflammation and the hepatic interferon pathway.

Ban-xia-xie-xin-tang ameliorates hepatic steatosis by regulating Cidea and Cidec expression in HFD-fed mice

BACKGROUND

Ban-xia-xie-xin-tang (BXXXT) has been applied in treating metabolic diseases, such as nonalcohol fatty liver disease, diabetes mellitus, and obesity. However, the underlying molecular mechanism of BXXXT in treating diabetes mellitus is unknown.

PURPOSE

To clarify the underlying molecular mechanism of BXXXT in alleviating hepatic steatosis in high-fat diet (HFD)-fed mice.

METHODS

After 12 weeks of HFD treatment, mice were administered BXXXT for 4 weeks. The main chemical components of BXXXT were identified by UPLC-TQ-MS/MS. Indicators associated with insulin resistance and lipid metabolism were detected. The effect of improving glucose and lipid metabolism between BXXXT and the different components was compared. Differentially expressed genes (DEGs) were identified by hepatic transcriptomics. Key DEGs and proteins were further detected by real-time quantitative polymerase chain reaction, western blotting, immunohistochemistry, and immunofluorescence staining. LDs and mitochondria were detected by transmission electron microscopy.

RESULTS

First of all, our data demonstrated that the capacity to improve glucose and lipid metabolism for BXXXT was significantly superior to different components of BXXXT. BXXXT was found to improve HFD-induced insulin resistance. Moreover, BXXXT decreased weight, serum/hepatic triglycerides, total cholesterol, and FFAs to alleviate HFD-induced hepatic steatosis. According to the results of the hepatic transcription, Cidea and Cidec were identified as critical DEGs for promoting LD fusion and reducing FFAs β-oxidation in mitochondria and peroxisome resulting in hepatic steatosis, which was reversed by BXXXT.

CONCLUSION

BXXXT ameliorates HFD-induced hepatic steatosis and insulin resistance by increasing Cidea and Cidec-mediated mitochondrial and peroxisomal fatty acid oxidation, which may provide a potential strategy for therapy of NAFLD and T2DM.

Crossbred Sows Fed a Western Diet during Pre-Gestation, Gestation, Lactation, and Post-Lactation Periods Develop Signs of Lean Metabolic Syndrome That Are Partially Attenuated by Spirulina Supplementation

Excessive dietary intake of fats and sugars (“Western diet”, WD) is one of the leading causes of obesity. The consumption of the microalga Arthrospira platensis (spirulina, Sp) is increasing due to its presumed health benefits. Both WD and Sp are also consumed by pregnant and breastfeeding women. This study investigated if gestating and lactating domestic pigs are an appropriate model for WD-induced metabolic disturbances similar to those observed in humans and if Sp supplementation may attenuate any of these adverse effects. Pigs were fed a WD high in fat, sugars, and cholesterol or a control diet. Half of the animals per diet group were supplemented with 20 g Sp per day. The WD did not increase body weight or adipose tissue accumulation but led to metabolic impairments such as higher cholesterol concentration in plasma, lower IGF1 plasma levels, and signs of hepatic damage compared to the control group. Spirulina supplementation could not reduce all the metabolic impairments observed in WD-fed animals. These findings indicate limited suitability of gestating and lactating domestic pigs as a model for WD but a certain potential of low-dose Sp supplementation to partially attenuate negative WD effects.

Non-alcoholic fatty liver disease: a multi-system disease influenced by ageing and sex, and affected by adipose tissue and intestinal function

In recent years, a wealth of factors are associated with increased risk of developing non-alcoholic fatty liver disease (NAFLD) and NAFLD is now thought to increase the risk of multiple extra-hepatic diseases. The aim of this review is first to focus on the role of ageing and sex as key, poorly understood risk factors in the development and progression of NAFLD. Secondly, we aim to discuss the roles of white adipose tissue (WAT) and intestinal dysfunction, as producers of extra-hepatic factors known to further contribute to the pathogenesis of NAFLD. Finally, we aim to summarise the role of NAFLD as a multi-system disease affecting other organ systems beyond the liver. Both increased age and male sex increase the risk of NAFLD and this may be partly driven by alterations in the distribution and function of WAT. Similarly, changes in gut microbiota composition and intestinal function with ageing and chronic overnutrition are likely to contribute to the development of NAFLD both directly (i.e. by affecting hepatic function) and indirectly via exacerbating WAT dysfunction. Consequently, the presence of NAFLD significantly increases the risk of various extra-hepatic diseases including CVD, type 2 diabetes mellitus, chronic kidney disease and certain extra-hepatic cancers. Thus changes in WAT and intestinal function with ageing and chronic overnutrition contribute to the development of NAFLD – a multi-system disease that subsequently contributes to the development of other chronic cardiometabolic diseases.

Meta-Inflammation and De Novo Lipogenesis Markers Are Involved in Metabolic Associated Fatty Liver Disease Progression in BTBR ob/ob Mice

Metabolic associated fatty liver disease (MAFLD) is a hepatic manifestation of metabolic syndrome and usually associated with obesity and diabetes. Our aim is to characterize the pathophysiological mechanism involved in MAFLD development in Black Tan and brachyuric (BTBR) insulin-resistant mice in combination with leptin deficiency (ob/ob). We studied liver morphology and biochemistry on our diabetic and obese mice model (BTBR ob/ob) as well as a diabetic non-obese control (BTBR + streptozotocin) and non-diabetic control mice (BTBR wild type) from 4–22 weeks. Lipid composition was assessed, and lipid related pathways were studied at transcriptional and protein level. Microvesicular steatosis was evident in BTBR ob/ob from week 6, progressing to macrovesicular in the following weeks. At 12th week, inflammatory clusters, activation of STAT3 and Nrf2 signaling pathways, and hepatocellular ballooning. At 22 weeks, the histopathological features previously observed were maintained and no signs of fibrosis were detected. Lipidomic analysis showed profiles associated with de novo lipogenesis (DNL). BTBR ob/ob mice develop MAFLD profile that resemble pathological features observed in humans, with overactivation of inflammatory response, oxidative stress and DNL signaling pathways. Therefore, BTBR ob/ob mouse is an excellent model for the study of the steatosis to steatohepatitis transition.

Transcriptomic analysis reveals a novel regulatory factor of ECHDC1 involved in lipid metabolism of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the highest incidence of chronic liver disease worldwide characterized by lipid accumulation in the liver. The full understanding of the lipogenesis of NAFLD is extreme importance. Here, whole-genome transcriptome analysis was performed on liver tissues of NAFLD patients and healthy controls to identify the differentially expressed genes and find new pathways and target genes related to the lipogenesis of NAFLD. Combined with the Gene Expression Omnibus (GEO) database, we found 86 overlapping genes, many of which are related to lipid metabolism of NAFLD. ECHDC1 is one of 86 overlapping genes, and its role in NAFLD has not been reported. The expression of ECHDC1 was significantly increased in liver tissue of patients with NAFLD than that of healthy controls, and oil Red O intensity was positively correlated with the expression levels of ECHDC1. Inhibition of ECHDC1 expression in HepG2 cells by RNAi significantly reduced intracellular lipid droplet number in vitro. In summary, this study analyzed pathogenic factors related to NAFLD at the whole-genome level and demonstrated that ECHDC1 may be involved in the occurrence and development of NAFLD by regulating hepatic lipid metabolism.

The docosahexaenoic acid derivatives, diHEP-DPA and TH-DPA, synthesized via recombinant lipoxygenase, ameliorate disturbances in lipid metabolism and liver inflammation in high fat diet-fed mice

7S,15R-Dihydroxy-16S,17S-epoxy-docosapentaenoic acid (diHEP-DPA) and 7S,15R,16S,17S-tetrahydroxy-docosapentaenoic acid (TH-DPA) are two novel lipid mediators derived from docosahexaenoic acid (DHA) that we previously synthesized via combined enzymatic and chemical reactions. In the present study, we investigated the effects of these compounds on disturbances in lipid metabolism and liver inflammation induced by a high fat diet (HFD) in mice. Male BALB/c mice were randomly divided into four groups (n = 10/group): controls, HFD only, HFD + diHEP-DPA, and HFD + TH-DPA. Mice in HFD + diHEP-DPA and HFD + TH-DPA groups were orally administered 20 μg/kg of diHEP-DPA or TH-DPA, respectively. Measurements of adipose accumulation and liver inflammation showed that both diHEP-DPA and TH-DPA decreased adipose tissue mass and liver color depth, as well as total cholesterol, triglycerides, and low-density lipoprotein-cholesterol in the serum of HFD-fed mice compared with mice in the HFD-only group, while elevating high-density lipoprotein-cholesterol. Both of them also decreased hepatic expression of genes encoding lipid synthesis-related proteins (PPARγ, SIRT1, SREBP-1c and FASN) and increased the expression of genes encoding proteins involved in lipid degradation (PPARα and CPT-1) in the liver. Western blotting and quantitative RT-PCR confirmed that diHEP-DPA or TH-DPA administration modulated the expression of inflammation-related genes (TNF-α and IL-6) and inhibited activation of the NF-κB signaling pathway in livers of HFD-fed mice. Taken together, our data indicate that diHEP-DPA and TH-DPA ameliorate liver inflammation and inhibit HFD-induced obesity in mice.

Polystyrene nanoplastics potentiate the development of hepatic fibrosis in high fat diet fed mice

Polystyrene nanoparticles (PS-NPs) as an issue of global environmental concern, have been shown to induce hepatic toxicity via triggering oxidative injury and inflammation. Non-alcoholic fatty liver disease (NAFLD) is initiated when excessive lipid is accumulated in the liver and will proceed to liver fibrosis with repeatedly chronic liver injury. In this study, we examined whether intravenous injection of PS-NPs could enhance the hepatic toxicity and potentiate the development of liver fibrosis in experimental high fat diet (HFD)-induced mice. The results demonstrated that PS-NPs could aggravate chronic hepatitis by interfere with liver lipid metabolism in HFD induced mice. Further, hepatic tissue in PS-NPs treated HFD mice displayed substantially lowered superoxide dismutase (SOD) activity, which confirming the oxidative stress induced by PS-NPs. PS-NPs exposure also resulted in the up-regulation of inflammation response in liver, as evidenced by the enhanced infiltration of Kupffer cells (KCs) and elevated expression of pro-inflammatory related indicators. Meanwhile, Masson trichrome staining revealed that PS-NPs could aggravate steatohepatitis with higher collagen fiber in HFD fed mice. Our data suggests that PS-NPs can induce oxidative stress and inflammation in HDF-induced experimental mice and further aggravate liver fibrosis, which highlight the potential health risks of PS-NPs.

Partial Replacement of Dietary Fat with Krill Oil or Coconut Oil Alleviates Dyslipidemia by Partly Modulating Lipid Metabolism in Lipopolysaccharide-Injected Rats on a High-Fat Diet

This study investigated the effects of partial replacement of dietary fat with krill oil (KO) or coconut oil (CO) on dyslipidemia and lipid metabolism in rats fed with a high-fat diet (HFD). Sprague Dawley rats were divided into three groups as follows: HFD, HFD + KO, and HFD + CO. The rats were fed each diet for 10 weeks and then intraperitoneally injected with phosphate-buffered saline (PBS) or lipopolysaccharide (LPS) (1 mg/kg). The KO- and CO-fed rats exhibited lower levels of serum lipids and aspartate aminotransferases than those of the HFD-fed rats. Rats fed with HFD + KO displayed significantly lower hepatic histological scores and hepatic triglyceride (TG) content than rats fed with HFD. The KO supplementation also downregulated the adipogenic gene expression in the liver. When treated with LPS, the HFD + KO and HFD + CO groups reduced the adipocyte size in the epididymal white adipose tissues (EAT) relative to the HFD group. These results suggest that KO and CO could improve lipid metabolism dysfunction.

Sodium salicylate rewires hepatic metabolic pathways in obesity and attenuates IL-1β secretion from adipose tissue - implications for obesity-impaired reverse cholesterol transport

Introduction

High-fat diet (HFD)-induced obesity impairs clearance of cholesterol through the Reverse Cholesterol Transport (RCT) pathway, with downregulation in hepatic expression of cholesterol and bile acid transporters, namely ABCG5/8 and ABCB11, and reduced high-density lipoprotein (HDL) cholesterol efflux capacity (CEC). In the current study, we hypothesized that the development of hepatosteatosis, secondary to adipose-tissue dysfunction, contributes to obesity-impaired RCT and that such effects could be mitigated using the anti-inflammatory drug sodium salicylate (NaS).

Materials and methods

C57BL/6J mice, fed HFD ± NaS or low-fat diet (LFD) for 24 weeks, underwent glucose and insulin tolerance testing. The ³H-cholesterol movement from macrophage-to-feces was assessed in vivo. HDL-CEC was determined ex vivo. Cytokine secretion from adipose-derived stromal vascular fraction (SVF) cells was measured ex vivo. Liver and HDL proteins were determined by mass spectrometry and analyzed using Ingenuity Pathway Analysis.

Results

NaS delayed HFD-induced weight gain, abrogated priming of pro-IL-1β in SVFs, attenuated insulin resistance, and prevented steatohepatitis (ectopic fat accumulation in the liver). Prevention of hepatosteatosis coincided with increased expression of PPAR-alpha/beta-oxidation proteins with NaS and reduced expression of LXR/RXR-induced proteins including apolipoproteins. The latter effects were mirrored within the HDL proteome in circulation. Despite remarkable protection shown against steatosis, HFD-induced hypercholesterolemia and repression of the liver-to-bile cholesterol transporter, ABCG5/8, could not be rescued with NaS.

Discussions and conclusions

The cardiometabolic health benefits of NaS may be attributed to the reprogramming of hepatic metabolic pathways to increase fatty acid utilization in the settings of nutritional overabundance. Reduced hepatic cholesterol levels, coupled with reduced LXR/RXR-induced proteins, may underlie the lack of rescue of ABCG5/8 expression with NaS. This remarkable protection against HFD-induced hepatosteatosis did not translate to improvements in cholesterol homeostasis.

•

Sodium salicylate (NaS) initially delays weight-gain in mice fed high-fat diet (HFD) - catch-up evident in weeks 12–24.

•

NaS prevents HFD-induced insulin resistance, hepatosteatosis and pro-IL-1β priming in adipose tissue even upon weight-gain.

•

Hepatic expression of proteins involved in beta oxidation, oxidative phosphorylation and TCA cycle upregulated with NaS.

•

Hepatic expression of LXR/RXR proteins eg. apolipoproteins reduced with NaS; these effects were mirrored in HDL proteome.

•

NaS failed to improve HFD-impaired Reverse Cholesterol Transport or hypercholesterolemia despite preventing hepatosteatosis.

Correction of cilia structure and function alleviates multi-organ pathology in Bardet-Biedl syndrome mice

Bardet–Biedl syndrome (BBS) is a pleiotropic autosomal recessive ciliopathy affecting multiple organs. The development of potential disease-modifying therapy for BBS will require concurrent targeting of multi-systemic manifestations. Here, we show for the first time that monosialodihexosylganglioside accumulates in Bbs2^−/− cilia, indicating impairment of glycosphingolipid (GSL) metabolism in BBS. Consequently, we tested whether BBS pathology in Bbs2^−/− mice can be reversed by targeting the underlying ciliary defect via reduction of GSL metabolism. Inhibition of GSL synthesis with the glucosylceramide synthase inhibitor Genz-667161 decreases the obesity, liver disease, retinal degeneration and olfaction defect in Bbs2^−/− mice. These effects are secondary to preservation of ciliary structure and signaling, and stimulation of cellular differentiation. In conclusion, reduction of GSL metabolism resolves the multi-organ pathology of Bbs2^−/− mice by directly preserving ciliary structure and function towards a normal phenotype. Since this approach does not rely on the correction of the underlying genetic mutation, it might translate successfully as a treatment for other ciliopathies.

Orally administered anti-eotaxin-1 monoclonal antibody is biologically active in the gut and alleviates immune-mediated hepatitis: A novel anti-inflammatory personalized therapeutic approach

Personalized therapies are designed to optimize the safety-to-efficacy ratio by selecting patients with higher response rates based on specific biomarkers. Inflammation plays a vital role in the pathogenesis of non-alcoholic steatohepatitis (NASH), a common liver disorder. Eotaxin-1 plays a role in innate and adaptive immune responses. High eotaxin-1 levels are associated with diabetes and fatty liver disease and, therefore, serves as a biomarker for patient selection. The anti-eotaxin-1 monoclonal antibody is tailored for the personalized therapy of patients with inflammatory conditions due to high levels of eotaxin-1. To evaluate the biological activity and immunomodulatory effect of orally administered anti-eotaxin-1. C57B1/6 mice were treated with either oral or intra-peritoneal anti-eotaxin-1 antibody before induction of immune-mediated hepatitis using an injection of concanavalin A (ConA) and checked for liver injury and eotaxin-1 serum levels. Oral administration of anti-eotaxin-1 alleviated the immune-mediated liver injury. Serum alanine aminotransferase levels decreased to 1807 U/L, compared with 19025 U/L in untreated controls and 3657 U/L in mice treated with parenteral anti-eotaxin-1 (P < 0.005). A trend toward reduced serum eotaxin-1 levels was observed in treated mice, ranging from 594 pg/mL in the controls to 554 and 561 pg/mL in mice treated orally and intraperitoneally (P = 0.08, P = 0.06, respectively). Oral administration of anti-eotaxin-1 antibody shows biological activity in the gut and exerts a systemic immunomodulatory effect to alleviate immune-mediated hepatitis. The data suggest that testing for eotaxin-1 serum levels may enable screening patients with high-eotaxin-1 levels-associated NASH.

Lipid-injured hepatocytes release sOPN to improve macrophage migration via CD44 engagement and pFak-NFκB signaling

BACKGROUND

The key characteristics in the pathogenesis of nonalcoholic steatohepatitis (NASH) are hepatic lipotoxicity, inflammatory cell infiltration (activated macrophages, in part), and varying degrees of fibrosis. The fatty acid palmitate (PA) can cause hepatocyte cellular dysfunction, but whether and how this process contributes to macrophage-associated inflammation is not well understood. This study aimed to explore whether lipid-injured hepatocytes result in the secretion of osteopontin (sOPN), and how sOPN induces macrophage migration to steatosis hepatocytes.

METHODS

Human hepatocellular carcinoma HepG2 cells were incubated with PA to establish the lipotoxicity in hepatocytes model in vitro. The released sOPN was isolated, characterized, and applied to macrophage-like cells differentiated from the human monocytic cell line THP-1 cells. C57BL/6 mice were fed either chow or a diet high in fructose-fat-glucose (FFG) to induce NASH in vivo. Some NASH model mice were also given siSPP1 for two weeks to inhibit the expression of OPN. Related tissues were collected and analyzed by histology, immunofluorescence, ELISA, qRT-PCR, and western blotting.

RESULTS

PA upregulated OPN expression and release in human hepatocytes, which drove the migration of macrophages. Incubation of HepG2 cells with palmitate increased mRNA expression and secretion of OPN in cell culture supernatants. Compared with the BSA and siSPP1 groups, treatment with the supernatant derived from PA-treated hepatocytes promoted macrophage migration and activation. The sOPN induction of macrophage migration occurred via CD44 engagement and activation of the pFak-NFκB signaling pathway. Likewise, administration of siSPP1 to NASH mice inhibited the expression and release of OPN, which was associated with decreased liver dysfunction, inflammatory cell infiltration, and even fibrosis.

CONCLUSIONS

sOPN, which is released from lipid-injured hepatocytes, emerges as a cytokine driving the migration of macrophages, contributing to an inflammatory response in NASH.

Protective Effect of Cudrania tricuspidata Extract against High-Fat Diet Induced Nonalcoholic Fatty Liver Disease through Nrf-2/HO-1 Pathway

Nonalcoholic fatty liver disease is the most common chronic disease affecting a wide range of the world’s population and associated with obesity-induced metabolic syndrome. It is possibly emerging as a leading cause of life-threatening liver diseases for which a drug with a specific therapeutic target has not been developed yet. Previously, there have been reports on the benefits of Cudrania tricuspidata (CT) for treating obesity and diabetes via regulation of metabolic processes, such as lipogenesis, lipolysis, and inflammation. In this study, we investigated the ameliorative effect of orally administered 0.25% and 0.5% (w/w) CT mixed with high-fat diet (HFD) to C57BL/6J mice for 7 weeks. It was found that body weight, fat mass, hepatic mass, serum glucose level, and liver cholesterol levels were significantly reduced after CT treatment. In CT-treated HFD-fed mice, the mRNA expression levels of hepatic lipogenic and inflammatory cytokine-related genes were markedly reduced, whereas the expression level of epididymal lipogenic genes was increased. The mRNA expression level of beta-oxidation and Nrf-2/HO-1 genes significantly increased in CT-treated obese mice livers. We propose that CT alleviates hepatic steatosis by reducing oxidative stress and inflammation.

The ménage à trois of autophagy, lipid droplets and liver disease

Autophagic pathways cross with lipid homeostasis and thus provide energy and essential building blocks that are indispensable for liver functions. Energy deficiencies are compensated by breaking down lipid droplets (LDs), intracellular organelles that store neutral lipids, in part by a selective type of autophagy, referred to as lipophagy. The process of lipophagy does not appear to be properly regulated in fatty liver diseases (FLDs), an important risk factor for the development of hepatocellular carcinomas (HCC). Here we provide an overview on our current knowledge of the biogenesis and functions of LDs, and the mechanisms underlying their lysosomal turnover by autophagic processes. This review also focuses on nonalcoholic steatohepatitis (NASH), a specific type of FLD characterized by steatosis, chronic inflammation and cell death. Particular attention is paid to the role of macroautophagy and macrolipophagy in relation to the parenchymal and non-parenchymal cells of the liver in NASH, as this disease has been associated with inappropriate lipophagy in various cell types of the liver.Abbreviations: ACAT: acetyl-CoA acetyltransferase; ACAC/ACC: acetyl-CoA carboxylase; AKT: AKT serine/threonine kinase; ATG: autophagy related; AUP1: AUP1 lipid droplet regulating VLDL assembly factor; BECN1/Vps30/Atg6: beclin 1; BSCL2/seipin: BSCL2 lipid droplet biogenesis associated, seipin; CMA: chaperone-mediated autophagy; CREB1/CREB: cAMP responsive element binding protein 1; CXCR3: C-X-C motif chemokine receptor 3; DAGs: diacylglycerols; DAMPs: danger/damage-associated molecular patterns; DEN: diethylnitrosamine; DGAT: diacylglycerol O-acyltransferase; DNL: de novo lipogenesis; EHBP1/NACSIN (EH domain binding protein 1); EHD2/PAST2: EH domain containing 2; CoA: coenzyme A; CCL/chemokines: chemokine ligands; CCl_4: carbon tetrachloride; ER: endoplasmic reticulum; ESCRT: endosomal sorting complexes required for transport; FA: fatty acid; FFAs: free fatty acids; FFC: high saturated fats, fructose and cholesterol; FGF21: fibroblast growth factor 21; FITM/FIT: fat storage inducing transmembrane protein; FLD: fatty liver diseases; FOXO: forkhead box O; GABARAP: GABA type A receptor-associated protein; GPAT: glycerol-3-phosphate acyltransferase; HCC: hepatocellular carcinoma; HDAC6: histone deacetylase 6; HECT: homologous to E6-AP C-terminus; HFCD: high fat, choline deficient; HFD: high-fat diet; HSCs: hepatic stellate cells; HSPA8/HSC70: heat shock protein family A (Hsp70) member 8; ITCH/AIP4: itchy E3 ubiquitin protein ligase; KCs: Kupffer cells; LAMP2A: lysosomal associated membrane protein 2A; LDs: lipid droplets; LDL: low density lipoprotein; LEP/OB: leptin; LEPR/OBR: leptin receptor; LIPA/LAL: lipase A, lysosomal acid type; LIPE/HSL: lipase E, hormone sensitive type; LIR: LC3-interacting region; LPS: lipopolysaccharide; LSECs: liver sinusoidal endothelial cells; MAGs: monoacylglycerols; MAPK: mitogen-activated protein kinase; MAP3K5/ASK1: mitogen-activated protein kinase kinase kinase 5; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MCD: methionine-choline deficient; MGLL/MGL: monoglyceride lipase; MLXIPL/ChREBP: MLX interacting protein like; MTORC1: mechanistic target of rapamycin kinase complex 1; NAFLD: nonalcoholic fatty liver disease; NAS: NAFLD activity score; NASH: nonalcoholic steatohepatitis; NPC: NPC intracellular cholesterol transporter; NR1H3/LXRα: nuclear receptor subfamily 1 group H member 3; NR1H4/FXR: nuclear receptor subfamily 1 group H member 4; PDGF: platelet derived growth factor; PIK3C3/VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; PLIN: perilipin; PNPLA: patatin like phospholipase domain containing; PNPLA2/ATGL: patatin like phospholipase domain containing 2; PNPLA3/adiponutrin: patatin like phospholipase domain containing 3; PPAR: peroxisome proliferator activated receptor; PPARA/PPARα: peroxisome proliferator activated receptor alpha; PPARD/PPARδ: peroxisome proliferator activated receptor delta; PPARG/PPARγ: peroxisome proliferator activated receptor gamma; PPARGC1A/PGC1α: PPARG coactivator 1 alpha; PRKAA/AMPK: protein kinase AMP-activated catalytic subunit; PtdIns3K: class III phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; PTEN: phosphatase and tensin homolog; ROS: reactive oxygen species; SE: sterol esters; SIRT1: sirtuin 1; SPART/SPG20: spartin; SQSTM1/p62: sequestosome 1; SREBF1/SREBP1c: sterol regulatory element binding transcription factor 1; TAGs: triacylglycerols; TFE3: transcription factor binding to IGHM enhancer 3; TFEB: transcription factor EB; TGFB1/TGFβ: transforming growth factor beta 1; Ub: ubiquitin; UBE2G2/UBC7: ubiquitin conjugating enzyme E2 G2; ULK1/Atg1: unc-51 like autophagy activating kinase 1; USF1: upstream transcription factor 1; VLDL: very-low density lipoprotein; VPS: vacuolar protein sorting; WIPI: WD-repeat domain, phosphoinositide interacting; WDR: WD repeat domain.

Fenofibrate Regulates Visceral Obesity and Nonalcoholic Steatohepatitis in Obese Female Ovariectomized C57BL/6J Mice

Fibrates, including fenofibrate, are a class of hypolipidemic drugs that activate peroxisome proliferator-activated receptor α (PPARα), which in-turn regulates the expression of lipid and lipoprotein metabolism genes. We investigated whether fenofibrate can reduce visceral obesity and nonalcoholic fatty liver disease via adipose tissue PPARα activation in female ovariectomized (OVX) C57BL/6J mice fed a high-fat diet (HFD), a mouse model of obese postmenopausal women. Fenofibrate reduced body weight gain (-38%, p < 0.05), visceral adipose tissue mass (-46%, p < 0.05), and visceral adipocyte size (-20%, p < 0.05) in HFD-fed obese OVX mice. In addition, plasma levels of alanine aminotransferase and aspartate aminotransferase, as well as free fatty acids, triglycerides, and total cholesterol, were decreased. Fenofibrate also inhibited hepatic lipid accumulation (-69%, p < 0.05) and infiltration of macrophages (-72%, p < 0.05), while concomitantly upregulating the expression of fatty acid β-oxidation genes targeted by PPARα and decreasing macrophage infiltration and mRNA expression of inflammatory factors in visceral adipose tissue. These results suggest that fenofibrate inhibits visceral obesity, as well as hepatic steatosis and inflammation, in part through visceral adipose tissue PPARα activation in obese female OVX mice.

The development of nonalcoholic steatohepatitis is subjected to breeder dependent variation in guinea pigs

Variability in disease development due to differences in strains and breeders constitutes a substantial challenge in preclinical research. However, the impact of the breeder on non-alcoholic steatohepatitis (NASH) is not yet fully elucidated. This retrospective study investigates NASH development in guinea pigs from Charles River or Envigo fed a high fat diet (20% fat, 15% sucrose, 0.35% cholesterol) for 16 or 24/25 weeks. Charles River animals displayed more severe NASH, with higher steatosis (p < 0.05 at week 16), inflammation (p < 0.05 at both week), fibrosis (p < 0.05 at week 16) and disease activity (p < 0.05 at both weeks). Accordingly, alanine and aspartate aminotransferase were increased at week 24/25 (p < 0.01). Hepatic expression of inflammatory (Ccl2, Cxcl8) and fibrotic (Pdgf, Serpine1, Col1a1) genes was also increased (p < 0.05). Differences were observed in healthy chow (4% fat, 0% sucrose, 0% cholesterol) fed animals: Envigo animals displayed higher relative liver weights (p < 0.01 at both weeks), liver cholesterol (p < 0.0001 at week 24/25) and aspartate aminotransferase (p < 0.05 at week 16), but lower levels of alkaline phosphatase (p < 0.0001 at week 24/25). These findings accentuates the importance of the breeder and its effect on NASH development and severity. Consequently, this may affect reproducibility, study comparison and limit the potential of developing novel therapies.

Effects of Long-Term DHA Supplementation and Physical Exercise on Non-Alcoholic Fatty Liver Development in Obese Aged Female Mice

Obesity and aging are associated to non-alcoholic fatty liver disease (NAFLD) development. Here, we investigate whether long-term feeding with a docosahexaenoic acid (DHA)-enriched diet and aerobic exercise, alone or in combination, are effective in ameliorating NAFLD in aged obese mice. Two-month-old female C57BL/6J mice received control or high fat diet (HFD) for 4 months. Then, the diet-induced obese (DIO) mice were distributed into four groups: DIO, DIO + DHA (15% dietary lipids replaced by a DHA-rich concentrate), DIO + EX (treadmill running), and DIO + DHA + EX up to 18 months. The DHA-rich diet reduced liver steatosis in DIO mice, decreasing lipogenic genes (Dgat2, Scd1, Srebp1c), and upregulated lipid catabolism genes (Hsl/Acox) expression. A similar pattern was observed in the DIO + EX group. The combination of DHA + exercise potentiated an increase in Cpt1a and Ppara genes, and AMPK activation, key regulators of fatty acid oxidation. Exercise, alone or in combination with DHA, significantly reversed the induction of proinflammatory genes (Mcp1, Il6, Tnfα, Tlr4) in DIO mice. DHA supplementation was effective in preventing the alterations induced by the HFD in endoplasmic reticulum stress-related genes (Ern1/Xbp1) and autophagy markers (LC3II/I ratio, p62, Atg7). In summary, long-term DHA supplementation and/or exercise could be helpful to delay NAFLD progression during aging in obesity.

Adipose tissue remodelling in obese subjects is a determinant of presence and severity of fatty liver disease

AIMS

Experimental data suggest that visceral adipose tissue (VAT) dysfunction contributes to non-alcoholic fatty liver disease (NAFLD) development in obesity, however, data on humans are limited. Aims of this study were to investigate the relationship between NAFLD and VAT morphofunctional impairment and to determine whether the extent of VAT remodelling is associated with liver damage and metabolic alterations in obesity.

METHODS

We analysed data from 40 obese individuals candidate to bariatric surgery in whom paired intraoperative liver and omental biopsies were performed for diagnosing NAFLD and VAT inflammation by immunohistochemistry and mRNA expression studies.

RESULTS

Within our study population, NAFLD was significantly associated with greater VAT CD68⁺ macrophages infiltration (P = .04), fibrosis (P = .04) and impaired microvascular density (P = .03) as well as increased expression of markers of local hypoxia, apoptosis and inflammation (UNC5B, CASP7, HIF1-α, IL-8, MIP2, WISP-1, all P < .01). The degree of VAT inflammation correlated with the severity of hepatic injury (steatosis, inflammation, fibrosis; all P < .01) and impaired gluco-metabolic profile.

CONCLUSIONS

In obese patients, NAFLD is associated in a dose-dependent manner with signs of VAT remodelling, which reflect more severe clinical metabolic impairment. Our study depicts morphological alterations and novel mediators of VAT dysfunction, adding knowledge for future therapeutic approaches to NAFLD and its metabolic complications.

Blockade of High-Fat Diet Proteomic Phenotypes Using Exercise as Prevention or Treatment

The increasing consumption of high-fat foods combined with a lack of exercise is a major contributor to the burden of obesity in humans. Aerobic exercise such as running is known to provide metabolic benefits, but how the overconsumption of a high-fat diet (HFD) and exercise interact is not well characterized at the molecular level. Here, we examined the plasma proteome in mice for the effects of aerobic exercise as both a treatment and as a preventative regimen for animals on either a HFD or a healthy control diet. This analysis detected large changes in the plasma proteome induced by the HFD, such as increased abundance of SERPINA7, ALDOB, and downregulation of SERPINA1E and complement factor D (CFD; adipsin). Some of these changes were significantly reverted using exercise as a preventative measure but not as a treatment regimen. To determine if either the intensity or duration of exercise influenced the outcome, we compared high-intensity interval training and endurance running. Endurance running slightly outperformed high-intensity interval training exercise, but overall, both provided similar reversion in abundance of plasma proteins modulated by the HFD, including SERPINA7, apolipoprotein E, SERPINA1E, and CFD. Finally, we compared the changes induced by overconsumption of a HFD with previous data from mice fed on an isocaloric high-saturated fatty acid or polyunsaturated fatty acid diet. This identified several common changes, including not only increased apolipoprotein C-II and apolipoprotein E but also highlighted changes specific for overconsumption of a HFD (fructose-bisphosphate aldolase B, SERPINA7, and CFD), saturated fatty acid-based diets (SERPINA1E), or polyunsaturated fatty acid-based diets (haptoglobin). Together, these data highlight the importance of early intervention with exercise to revert HFD-induced phenotypes and suggest some of the molecular mechanisms leading to the changes in the plasma proteome generated by HFD consumption. Web-based interactive visualizations are provided for this dataset (larancelab.com/hfd-exercise), which give insight into diet and exercise phenotypic interactions on the plasma proteome.

Phenethyl Isothiocyanate Protects against High Fat/Cholesterol Diet-Induced Obesity and Atherosclerosis in C57BL/6 Mice

This study concerns obesity-related atherosclerosis, hyperlipidemia, and chronic inflammation. We studied the anti-obesity and anti-atherosclerosis effects of phenethyl isothiocyanate (PEITC) and explored their underlying mechanisms. We established an animal model of high fat/cholesterol-induced obesity in C57BL/6 mice fed for 13 weeks. We divided the mice into five groups: control (CON), high fat/cholesterol (HFCD), HFCD with 3 mg/kg/day gallic acid (HFCD + G), and HFCD with PEITC (30 and 75 mg/kg/day; HFCD + P30 and P75). The body weight, total cholesterol, and triglyceride were significantly lower in the HFCD + P75 group than in the HFCD group. Hepatic lipid accumulation and atherosclerotic plaque formation in the aorta were significantly lower in both HFCD + PEITC groups than in the HFCD group, as revealed by hematoxylin and eosin (H&E) staining. To elucidate the mechanism, we identified the expression of genes related to inflammation, reverse cholesterol transport, and lipid accumulation pathway in the liver. The expression levels of peroxisome proliferator activated receptor gamma (PPARγ), liver-X-receptor α (LXR-α), and ATP binding cassette subfamily A member 1 (ABCA1) were increased, while those of scavenger receptor A (SR-A1), cluster of differentiation 36 (CD36), and nuclear factor-kappa B (NF-κB) were decreased in the HFCD + P75 group compared with those in the HFCD group. Moreover, PEITC modulated H3K9 and H3K27 acetylation, H3K4 dimethylation, and H3K27 di-/trimethylation in the HFCD + P75 group. We, therefore, suggest that supplementation with PEITC may be a potential candidate for the treatment and prevention of atherosclerosis and obesity.

IL-18 but Not IL-1 Signaling Is Pivotal for the Initiation of Liver Injury in Murine Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is rising in prevalence, and a better pathophysiologic understanding of the transition to its inflammatory phenotype (NASH) is key to the development of effective therapies. To evaluate the contribution of the NLRP3 inflammasome and its downstream effectors IL-1 and IL-18 in this process, we applied the true-to-life “American lifestyle-induced obesity syndrome” (ALiOS) diet mouse model. Development of obesity, fatty liver and liver damage was investigated in mice fed for 24 weeks according to the ALiOS protocol. Lipidomic changes in mouse livers were compared to human NAFLD samples. Receptor knockout mice for IL-1 and IL-18 were used to dissect the impact of downstream signals of inflammasome activity on the development of NAFLD. The ALiOS diet induced obesity and liver steatosis. The lipidomic changes closely mimicked changes in human NAFLD. A pro-inflammatory gene expression pattern in liver tissue and increased serum liver transaminases indicated early liver damage in the absence of histological evidence of NASH. Mechanistically, Il-18r^−/−- but not Il-1r^−/− mice were protected from early liver damage, possibly due to silencing of the pro-inflammatory gene expression pattern. Our study identified NLRP3 activation and IL-18R-dependent signaling as potential modulators of early liver damage in NAFLD, preceding development of histologic NASH.

Molecular mechanism of obesity-induced adipose tissue inflammation; the role of Mincle in adipose tissue fibrosis and ectopic lipid accumulation

Metabolic syndrome is a common metabolic disorder that involves multiple organs and is predominantly influenced by obesity, especially the accumulation of visceral fat. It is also known that macrophages that infiltrate obese adipose tissue play an important role in inflammation of the adipose tissue. Macrophage-inducible C-type lectin (Mincle), a new inflammatory regulator found in obese adipose tissue, is expressed in pro-inflammatory M1 macrophages in adipose tissue. In addition, Mincle is expressed in macrophages that form a crown-like structure, where dead or dying adipocytes are surrounded by pro-inflammatory M1 macrophages; within this crown-like structure, adipocyte-macrophage crosstalk may occur in close proximity. Although there is no significant difference in body weight between Mincle-deficient and wild-type mice under high-fat diet, the epididymal fat weight is significantly higher and the liver weight is significantly lower in Mincle-deficient mice than those in wild-type mice. It has been shown that adipose tissue inflammation and fibrosis are attenuated in Mincle-deficient mice when compared with wild-type mice. In addition, Mincle-deficient mice have reduced hepatic lipid accumulation and better glucose metabolism. These results suggest that Mincle signaling in adipose tissue macrophages activates adipose tissue fibroblasts, which leads to adipose tissue fibrosis.

Advanced liver steatosis accompanies an increase in hepatic inflammation, colonic, secondary bile acids and Lactobacillaceae/Lachnospiraceae bacteria in C57BL/6 mice fed a high-fat diet

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western countries, and the gut-liver axis is implicated in liver disease pathogenesis. We hypothesize that advanced liver steatosis accompanies an increase in hepatic inflammation, colonic secondary bile acids (BAs) and secondary BA-producing bacteria in mice fed a high-fat (HF) diet model of obesity. Four-week old male C57BL/6 mice were fed an HF (45% energy) or a low-fat (LF) (10% energy) diet for 21 weeks. At the end of the study, body weight and body fat percentage in the HF group were 0.23- and 0.41-fold greater than those in the LF group, respectively. Similarly, the HF group exhibited an increase in hepatic lipid droplets, inflammatory cell infiltration, inducible nitric oxide synthase, and hepatocellular ballooning (but without hepatic Mallory bodies) which are key histological features of advanced hepatic steatosis. Furthermore, RNA sequencing, qPCR and immunohistological methods found that nicotinamide n-methyltransferase and selenoprotein P, two inflammation-related hepatic genes, were upregulated in the HF group. Consistent with the hepatic inflammation, the levels of proinflammatory plasma-cytokines (TNF-α and IL6), colonic secondary BAs (LCA, DCA) and secondary BA producing bacteria (e.g., lactobacillaceae/Lachnospiraceae) were at least 0.5-fold greater in the HF group compared with the LF group. Taken together, the data demonstrate that advanced liver-steatosis is concurrent with an elevated level of hepatic inflammation, colonic secondary bile acids and their associated bacteria in mice fed an HF diet. These data suggest a potential gut-liver crosstalk at the stage of advanced liver-steatosis.

The Role of Lipophagy in the Development and Treatment of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) or metabolic (dysfunction) associated liver disease (MAFLD), is, with a global prevalence of 25%, the most common liver disorder worldwide. NAFLD comprises a spectrum of liver disorders ranging from simple steatosis to steatohepatitis, fibrosis, cirrhosis and eventually end-stage liver disease. The cause of NAFLD is multifactorial with genetic susceptibility and an unhealthy lifestyle playing a crucial role in its development. Disrupted hepatic lipid homeostasis resulting in hepatic triglyceride accumulation is an hallmark of NAFLD. This disruption is commonly described based on four pathways concerning 1) increased fatty acid influx, 2) increased de novo lipogenesis, 3) reduced triglyceride secretion, and 4) reduced fatty acid oxidation. More recently, lipophagy has also emerged as pathway affecting NAFLD development and progression. Lipophagy is a form of autophagy (i.e. controlled autolysosomal degradation and recycling of cellular components), that controls the breakdown of lipid droplets in the liver. Here we address the role of hepatic lipid homeostasis in NAFLD and specifically review the current literature on lipophagy, describing its underlying mechanism, its role in pathophysiology and its potential as a therapeutic target.

Inflammation and Ectopic Fat Deposition in the Aging Murine Liver Is Influenced by CCR2

Aging is associated with inflammation and metabolic syndrome, which manifests in the liver as nonalcoholic fatty liver disease (NAFLD). NAFLD can range in severity from steatosis to fibrotic steatohepatitis and is a major cause of hepatic morbidity. However, the pathogenesis of NAFLD in naturally aged animals is unclear. Herein, we performed a comprehensive study of lipid content and inflammatory signature of livers in 19-month-old aged female mice. These animals exhibited increased body and liver weight, hepatic triglycerides, and inflammatory gene expression compared with 3-month-old young controls. The aged mice also had a significant increase in F4/80⁺ hepatic macrophages, which coexpressed CD11b, suggesting a circulating monocyte origin. A global knockout of the receptor for monocyte chemoattractant protein (CCR2) prevented excess steatosis and inflammation in aging livers but did not reduce the number of CD11b⁺ macrophages, suggesting changes in macrophage accumulation precede or are independent from chemokine (C-C motif) ligand-CCR2 signaling in the development of age-related NAFLD. RNA sequencing further elucidated complex changes in inflammatory and metabolic gene expression in the aging liver. In conclusion, we report a previously unknown accumulation of CD11b⁺ macrophages in aged livers with robust inflammatory and metabolic transcriptomic changes. A better understanding of the hallmarks of aging in the liver will be crucial in the development of preventive measures and treatments for end-stage liver disease in elderly patients.

Dietary wheat amylase trypsin inhibitors promote features of murine non-alcoholic fatty liver disease

We previously demonstrated that a common dietary protein component, wheat amylase trypsin inhibitors (ATI), stimulate intestinal macrophages and dendritic cells via toll like receptor 4. Activation of these intestinal myeloid cells elicits an inflammatory signal that is propagated to mesenteric lymph nodes, and that can facilitate extraintestinal inflammation. Mice were fed a well-defined high fat diet, with (HFD/ATI) or without (HFD) nutritionally irrelevant amounts of ATI. Mice on HFD/ATI developed only mild signs of intestinal inflammation and myeloid cell activation but displayed significantly higher serum triglycerides and transaminases compared to mice on HFD alone. Moreover, they showed increased visceral and liver fat, and a higher insulin resistance. ATI feeding promoted liver and adipose tissue inflammation, with M1-type macrophage polarization and infiltration, and enhanced liver fibrogenesis. Gluten, the major protein component of wheat, did not induce these pathologies. Therefore, wheat ATI ingestion in minute quantities comparable to human daily wheat consumption exacerbated features of the metabolic syndrome and non-alcoholic steatohepatitis, despite its irrelevant caloric value.

Variation in diagnostic NAFLD/NASH read-outs in paired liver samples from rodent models

INTRODUCTION

In animal models of non-alcoholic fatty liver disease (NAFLD), assessment of disease severity and treatment effects of drugs rely on histopathological scoring of liver biopsies. However, little is known about the sampling variation in liver samples from animal models of NAFLD, even though several histopathological hallmarks of the disease are known to be affected by sampling variation in patients. The aim of this study was to assess the sampling variation in multiple paired liver biopsies from three commonly used diet-induced rodent models of NAFLD.

METHODS

Eight male C57BL/6 mice, 8 male Sprague Dawley rats and 16 female Hartley guinea pigs were fed a NAFLD-inducing high-fat diet for 16 weeks (mice and rats), 20 or 24 weeks (guinea pigs). After the initial diet period, liver sections were sampled and subsequently assessed by histopathological scoring and biochemical analyses.

RESULTS

Fibrosis was heterogeneously distributed throughout the liver in mice, manifesting as both intra- and interlobular statistically significant differences. Hepatic triglyceride content showed interlobular differences in mice, and both intra- and interlobular differences in guinea pigs (24-week time point) all of which were statistically significant. Also, hepatic cholesterol content was subject to significant intra-lobular sampling variation in mice, and hepatic glycogen content differed significantly between lobes in mice and guinea pigs.

DISCUSSION

Dependent on animal model, both histopathological and biochemical end-points differed between sampling sites in the liver. Based on these findings, we recommend that sample site location is highly standardized and properly reported in order to minimize potential sampling variation and to optimize reproducibility and meaningful comparisons of preclinical studies of NAFLD.

Genetic inactivation of the LIGHT (TNFSF14) cytokine in mice restores glucose homeostasis and diminishes hepatic steatosis

AIMS/HYPOTHESIS

Non-alcoholic fatty liver disease (NAFLD) is frequently associated with type 2 diabetes mellitus. Progression of NAFLD is mediated, among other things, by activation of inflammatory pathways. In the present study, the role of the proinflammatory cytokine LIGHT (TNFSF14) was explored in NAFLD and type 2 diabetes mellitus in mice deficient for the cytokine.

METHODS

Light-deficient (Light^-/-) mice and WT controls were fed a regular chow diet (RCD) or a high-fat high-cholesterol diet (HFHCD) for 16 weeks. The expression of LIGHT and its receptors, herpes virus entry mediator (HVEM) and lymphotoxin β receptor (LTβR), was investigated in both dietary regimens. Glucose tolerance, insulin sensitivity, non-alcoholic fatty liver (NAFL), systemic and tissue inflammation, and metabolic gene expression were explored in Light^-/- and WT mice fed an RCD and an HFHCD. The effect of Light deficiency was also evaluated in hepatic tissue and in inflammation in HFHCD-fed Irs2^+/- mice with impaired insulin signalling.

RESULTS

Light deficiency did not have an effect on metabolism, in NAFL or in tissue and systemic inflammation, in RCD-fed WT mice. HVEM and LTβR were markedly increased in livers of HFHCD-fed WT mice compared with RCD-fed WT controls. In WT mice under HFHCD, Light deficiency improved glucose tolerance and insulin sensitivity. Non-alcoholic fatty liver disease activity (NAS) score, hepatic CD3⁺ T lymphocytes and F4/80⁺ macrophages were decreased in HFHCD-fed Light^-/- mice compared with HFHCD-fed WT controls. Consistent with a potential role of adipose tissue in hepatic homeostasis, Light^-/- mice exhibited augmented anti-inflammatory F4/80⁺CD206⁺ adipose tissue macrophages and reduced proinflammatory F4/80⁺CD11c⁺ adipose tissue macrophages. Moreover, adipose tissue explants from Light^-/- mice showed diminished secretion of monocyte chemoattractant protein 1 (MCP1), TNF-α and IL-17 cytokines. Circulating Light^-/- leucocytes consistently displayed augmented levels of the patrolling Ly6C^low monocytes, decreased Th9 T cell subset and diminished plasma TNF-α and IL-6 levels. Similarly, Light deficiency in Irs2^+/- mice, which display impaired insulin signalling, also reduced NAFL as well as systemic and adipose tissue inflammation. Analysis of hepatic gene expression in Light^-/- mouse livers showed reduced levels of Zbtb16, the transcription factor essential for natural killer T (NKT) cell function, and two genes related to NAFLD and fibrosis, Klf6 and Tlr4.

CONCLUSIONS/INTERPRETATION

These results indicate that Light deficiency in HFHCD improves hepatic glucose tolerance, and reduces hepatic inflammation and NAFL. This is accompanied by decreased systemic inflammation and adipose tissue cytokine secretion and by changes in the expression of key genes such as Klf6 and Tlr4 involved in NAFLD. These results suggest that therapies to block LIGHT-dependent signalling might be useful to restore hepatic homeostasis and to restrain NAFLD.

Soluble guanylate cyclase stimulator praliciguat attenuates inflammation, fibrosis, and end-organ damage in the Dahl model of cardiorenal failure

Reduced nitric oxide (NO) and a decrease in cGMP signaling mediated by soluble guanylate cyclase (sGC) has been linked to the development of several cardiorenal diseases. Stimulation of sGC is a potential means for enhancing cGMP production in conditions of reduced NO bioavailability. The purpose of our studies was to determine the effects of praliciguat, a clinical-stage sGC stimulator, in a model of cardiorenal failure. Dahl salt-sensitive rats fed a high-salt diet to induce hypertension and organ damage were treated with the sGC stimulator praliciguat to determine its effects on hemodynamics, biomarkers of inflammation, fibrosis, tissue function, and organ damage. Praliciguat treatment reduced blood pressure, improved cardiorenal damage, and attenuated the increase in circulating markers of inflammation and fibrosis. Notably, praliciguat affected markers of renal damage at a dose that had minimal effect on blood pressure. In addition, liver fibrosis and circulating markers of tissue damage were attenuated in praliciguat-treated rats. Stimulation of the NO-sGC-cGMP pathway by praliciguat attenuated or normalized indicators of chronic inflammation, fibrosis, and tissue dysfunction in the Dahl salt-sensitive rat model. Stimulation of sGC by praliciguat may present an effective mechanism for treating diseases linked to NO deficiency, particularly those associated with cardiac and renal failure. Praliciguat is currently being evaluated in patients with diabetic nephropathy and heart failure with preserved ejection fraction.

Adipocyte JAK2 mediates spontaneous metabolic liver disease and hepatocellular carcinoma

Non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) are liver manifestations of the metabolic syndrome and can progress to hepatocellular carcinoma (HCC). Loss of Growth Hormone (GH) signaling is reported to predispose to NAFLD and NASH through direct actions on the liver. Here, we report that aged mice lacking hepatocyte Jak2 (JAK2L), an obligate transducer of Growth Hormone (GH) signaling, spontaneously develop the full spectrum of phenotypes found in patients with metabolic liver disease, beginning with insulin resistance and lipodystrophy and manifesting as NAFLD, NASH and even HCC, independent of dietary intervention. Remarkably, insulin resistance, metabolic liver disease, and carcinogenesis are prevented in JAK2L mice via concomitant deletion of adipocyte Jak2 (JAK2LA). Further, we demonstrate that GH increases hepatic lipid burden but does so indirectly via signaling through adipocyte JAK2. Collectively, these data establish adipocytes as the mediator of GH-induced metabolic liver disease and carcinogenesis. In addition, we report a new spontaneous model of NAFLD, NASH, and HCC that recapitulates the natural sequelae of human insulin resistance-associated disease progression. The work presented here suggests a attention be paid towards inhibition of adipocyte GH signaling as a therapeutic target of metabolic liver disease.

Dietary Methionine Restriction Reduces Inflammation Independent of FGF21 Action

OBJECTIVE

Methionine restriction (MR) decreases inflammation and improves markers of metabolic disease in rodents. MR also increases hepatic and circulating concentrations of fibroblast growth factor 21 (FGF21). Emerging evidence has suggested that FGF21 exerts anti-inflammatory effects. The purpose of this study was to determine the role of FGF21 in mediating the MR-induced reduction in inflammation.

METHODS

Wild-type and Fgf21^-/- mice were fed a high-fat (HF) control or HF-MR diet for 8 weeks. In a separate experiment, mice were fed a HF diet (HFD) for 10 weeks. Vehicle or recombinant FGF21 (13.6 µg/d) was administered via osmotic minipump for an additional 2 weeks. Inflammation and metabolic parameters were measured.

RESULTS

Fgf21^-/- mice were more susceptible to HFD-induced inflammation, and MR reduced inflammation in white adipose tissue (WAT) and liver of Fgf21^-/- mice. MR downregulated activity of signal transducer and activator of transcription 3 in WAT of both genotypes. FGF21 administration reduced hepatic lipids and blood glucose concentrations. However, there was little effect of FGF21 on inflammatory gene expression in liver or adipose tissue or circulating cytokines.

CONCLUSIONS

MR reduces inflammation independent of FGF21 action. Endogenous FGF21 is important to protect against the development of HFD-induced inflammation in liver and WAT, yet administration of low-dose FGF21 has little effect on markers of inflammation.

Effect of liver fatty acid binding protein (L-FABP) gene ablation on lipid metabolism in high glucose diet (HGD) pair-fed mice

Liver fatty acid binding protein (L-FABP) is the major fatty acid binding/"chaperone" protein in hepatic cytosol. Although fatty acids can be derived from the breakdown of dietary fat and glucose, relatively little is known regarding the impact of L-FABP on phenotype in the context of high dietary glucose. Potential impact was examined in wild-type (WT) and Lfabp gene ablated (LKO) female mice fed either a control or pair-fed high glucose diet (HGD). WT mice fed HGD alone exhibited decreased whole body weight gain and weight gain/kcal food consumed-both as reduced lean tissue mass (LTM) and fat tissue mass (FTM). Conversely, LKO alone increased weight gain, lean tissue mass, and fat tissue mass while decreasing serum β-hydroxybutyrate (indicative of hepatic fatty acid oxidation)-regardless of diet. Both LKO alone and HGD alone significantly altered the serum lipoprotein profile and increased triacylglycerol (TG), but in HGD mice the LKO did not further exacerbate serum TG content. HGD had little effect on hepatic lipid composition in WT mice, but prevented the LKO-induced selective increase in hepatic phospholipid, free-cholesterol and cholesteryl-ester. Taken together, these findings suggest that high glucose diet diminished the effects of LKO on the whole body and lipid phenotype of these mice.