Using the PDCA cycle

FK-binding protein 5: Possible relevance to the pathogenesis of metabolic dysfunction and alcohol-associated liver disease

The FK506-binding protein (FKBP5) plays significant roles in mediating stress responses by interacting with glucocorticoids, participating in adipogenesis, and influencing various cellular pathways throughout the body. In this review, we described the potential role of FKBP5 in the pathogenesis of two common chronic liver diseases, metabolic dysfunction-associated steatotic liver disease (MASLD), and alcohol-associated liver disease (ALD). We provided an overview of the FK-binding protein family and elucidated their roles in cellular stress responses, metabolic diseases, and adipogenesis. We explored how FKBP5 may mechanistically influence the pathogenesis of MASLD and ALD and provided insights for further investigation into the role of FKBP5 in these two diseases.

RNF43/ZNRF3 loss predisposes to hepatocellular-carcinoma by impairing liver regeneration and altering the liver lipid metabolic ground-state

RNF43/ZNRF3 negatively regulate WNT signalling. Both genes are mutated in several types of cancers, however, their contribution to liver disease is unknown. Here we describe that hepatocyte-specific loss of Rnf43/Znrf3 results in steatohepatitis and in increase in unsaturated lipids, in the absence of dietary fat supplementation. Upon injury, Rnf43/Znrf3 deletion results in defective hepatocyte regeneration and liver cancer, caused by an imbalance between differentiation/proliferation. Using hepatocyte-, hepatoblast- and ductal cell-derived organoids we demonstrate that the differentiation defects and lipid alterations are, in part, cell-autonomous. Interestingly, ZNRF3 mutant liver cancer patients present poorer prognosis, altered hepatic lipid metabolism and steatohepatitis/NASH signatures. Our results imply that RNF43/ZNRF3 predispose to liver cancer by controlling the proliferative/differentiation and lipid metabolic state of hepatocytes. Both mechanisms combined facilitate the progression towards malignancy. Our findings might aid on the management of those RNF43/ZNRF3 mutated individuals at risk of developing fatty liver and/or liver cancer.

A Mitochondrial VDAC1-Based Peptide Greatly Suppresses Steatosis and NASH-Associated Pathologies in a Mouse Model

Non-alcoholic steatosis and non-alcoholic steatohepatitis (NASH) are liver pathologies characterized by severe metabolic alterations due to fat accumulation that lead to liver damage, inflammation, and fibrosis. We demonstrate that the voltage-dependent anion channel 1 (VDAC1)-based peptide R-Tf-D-LP4 arrested steatosis and NASH progression, as produced by a high-fat diet (HFD-32) in a mouse model, and reversed liver pathology to a normal-like state. VDAC1, a multi-functional mitochondrial protein, regulates cellular metabolic and energetic functions and apoptosis and interacts with many proteins. R-Tf-D-LP4 treatment eliminated hepatocyte ballooning degeneration, inflammation, and liver fibrosis associated with steatosis, NASH, and hepatocarcinoma, and it restored liver pathology-associated enzyme and glucose levels. Peptide treatment affected carbohydrate and lipid metabolism, increasing the expression of enzymes and factors associated with fatty acid transport to mitochondria, enhancing β-oxidation and thermogenic processes, yet decreasing the expression of enzymes and regulators of fatty acid synthesis. The VDAC1-based peptide thus offers a promising therapeutic approach for steatosis and NASH.

Fimasartan Ameliorates Nonalcoholic Fatty Liver Disease through PPARδ Regulation in Hyperlipidemic and Hypertensive Conditions

To investigate the effects of fimasartan on nonalcoholic fatty liver disease in hyperlipidemic and hypertensive conditions, the levels of biomarkers related to fatty acid metabolism were determined in HepG2 and differentiated 3T3-L1 cells treated by high fatty acid and liver and visceral fat tissue samples of spontaneously hypertensive rats (SHRs) given high-fat diet. In HepG2 cells and liver tissues, fimasartan was shown to increase the protein levels of peroxisome proliferator-activated receptor delta (PPARδ), phosphorylated 5' adenosine monophosphate-activated protein kinase (p-AMPK), phosphorylated acetyl-CoA carboxylase (p-ACC), malonyl-CoA decarboxylase (MCD), medium chain acyl-CoA dehydrogenase (MCAD), and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and it led to a decrease in the protein levels of 11 beta-hydroxysteroid dehydrogenase 1 (11β-HSDH1), fatty acid synthase (FAS), and tumor necrosis factor-alpha (TNF-α). Fimasartan decreased lipid contents in HepG2 and differentiated 3T3-L1 cells and liver tissues. In addition, fimasartan increased the adiponectin level in visceral fat tissues. The antiadipogenic effects of fimasartan were offset by PPARδ antagonist (GSK0660). Consequently, fimasartan ameliorates nonalcoholic fatty liver disease mainly through the activation of oxidative metabolism represented by PPARδ-AMPK-PGC-1α pathway.

Treatment of mouse liver slices with cholestatic hepatotoxicants results in down-regulation of Fxr and its target genes

BACKGROUND

Unexpected cholestasis substantially contributes to drug failure in clinical trials. Current models used for safety assessment in drug development do not accurately predict cholestasis in humans. Therefore, it is of relevance to develop new screening models that allow identifying drugs with cholestatic properties.

METHODS

We employed mouse precision cut liver slices (PCLS), which were incubated 24 h with two model cholestatic compounds: cyclosporin A (CsA) and chlorpromazine (CPZ). Subsequently, transcriptome analysis using DNA microarrays and q-PCR were performed to identify relevant biological processes and biomarkers. Additionally, histology was carried out and levels of triglycerides (TG) and bile acids (BA) were measured. To verify the ex vivo mouse data, these were compared with publically available human data relevant for cholestasis.

RESULTS

Whole genome gene expression analysis showed that CsA up-regulated pathways related to NF-κB, ER stress and inflammation. Both CsA and CPZ down-regulated processes related to extracellular matrix (ECM) remodelling, BA homeostasis, Fxr signalling, and energy metabolism. The differential expression of a number of characteristic genes (e.g. Abcg5, Abcg8, Klf15, and Baat) could be confirmed by q-PCR. Histology revealed that CsA but not CPZ induced "ballooning" of hepatocytes. No effects on TG and BA levels were observed after incubation of PCLS with CsA and CPZ. A substantial number of processes altered in CsA- and CPZ-treated mouse PCLS ex vivo was also found to be affected in liver biopsies of cholestatic patients.

CONCLUSION

The present study demonstrated that mouse PCLS can be used as a tool to identify mechanisms of action of cholestatic model compounds. The induction of general stress responses and down-regulated Fxr signalling could play a role in the development of drug induced cholestasis. Importantly, comparative data analysis showed that the ex vivo mouse findings are also relevant for human pathology. Moreover, this work provides a set of genes that are potentially useful to assess drugs for cholestatic properties.

[Non-alcoholic steatohepatitis induced by fast weight loss during the use of intragastric balloon--a case report]

Obesity is a chronic disease that has been considered an epidemic nowadays. It is associated to much co-morbidity, such as non-alcoholic fatty liver disease (NAFLD) and its complication, steatohepatitis. We report a case of a 58-year-old obese patient refractory to clinical treatment who was submitted to the use of intragastric balloon (BIB), developing steatohepatitis induced by fast weight loss.

Efficacy of rosiglitazone in treatment of nonalcoholic fatty liver disease and its relations with adiponectin

AIM: To explore an effective, safe and convenient method in the treatment of nonalcoholic fatty liver disease (NAFLD) and a marker in the pre-diction of the efficacy.

METHODS: One hundred and twenty-four patients diagnosed with NAFLD (except cirrhosis) were randomly divided into rosiglitazone (RSG) treatment group and placebo group (controls). After treatment with the corresponding methods, comparative analysis on the efficacy and serum adiponectin was performed between the two groups.

RESULTS: ESG significantly improved the liver function, levels of blood glucose, lipid and serum adiponectin, as well as insulin resistance (HOMA-IR) (P < 0.05). The total effective rates were markedly significantly between RSG group and placebo group (57/63 vs 37/61, P < 0.01). The levels of serum alanine aminotransferase (ALT) was significantly correlated with adiponectin level (r = -0.685, P < 0.01) and HOMA-IR (r = 0.447, P < 0.01). The safety was not notably different between the two groups (P > 0.05).

CONCLUSION: RSG is effective and safe in the treatment of NAFLD and serum adiponectin level can be used to predict its efficacy.

Early diet-induced non-alcoholic steatohepatitis in APOE2 knock-in mice and its prevention by fibrates

BACKGROUND/AIMS

The molecular mechanisms leading to Non-Alcoholic Steatohepatitis (NASH) are not fully understood. In mice, NASH can be inhibited by fenofibrate, a synthetic agonist for the nuclear receptor peroxisome proliferator activated receptor alpha, which regulates hepatic triglyceride metabolism. This study aimed to elucidate the relation between steatosis and inflammation in NASH in a human-like hyperlipidemic mouse model.

METHODS

Liver phenotype and gene expression were assessed in APOE2 knock-in mice that were fed a western-type high fat diet with or without co-administration of fenofibrate.

RESULTS

In response to a western diet, APOE2 knock-in mice developed NASH characterized by steatosis and inflammation. Strikingly, macrophage accumulation in the liver preceded the steatosis during progression of the disease. This phenotype was in line with gene expression patterns, which showed regulation of two major groups of genes, i.e. inflammatory and lipid genes. Fenofibrate treatment decreased hepatic macrophage accumulation and abolished steatosis. Moreover, a marked reduction in the expression of inflammatory genes occurred immediately after fenofibrate treatment.

CONCLUSIONS

These data indicate that inflammation might play an instrumental role during the development of NASH in this mouse model. Inhibition of NASH by fenofibrate may be due, at least in part, to its inhibitory effect on pro-inflammatory genes.

Nonalcoholic fatty liver disease treated by gastroplasty

Nonalcoholic steatohepatitis (NASH), which is the most severe histologic form of nonalcoholic fatty liver disease (NAFLD), is emerging as the most common clinically important form of liver disease in obese patients. The prevalence of NASH may increase with the rise in the rate of obesity and metabolic syndrome in affluent communities. The aim of this work is to describe clinical and histopathologic findings and correlate liver tissue damage to the length of duration of the obesity in the group of patients who underwent surgery as obesity treatment. Eighty-seven severely or morbidly obese patients underwent gastroplasty. Each patient was evaluated with complete clinical and laboratory medical assessment together with wedge liver biopsy taken from 59 unselected patients during the surgery. Patients were followed up for 41 months. Repeat liver biopsy was taken from 10 patients. Pathologic analysis recorded the presence and degree of steatosis, portal and lobular inflammation and fibrosis. Age, body mass index (BMI), and laboratory assessment correlated with pathologic data. Male patients showed more pronounced metabolic syndrome and fatty liver damage. Patients who become obese in childhood or as teenagers showed no differences in metabolic syndrome and NAFLD in mature age. There was statistically significant association between BMA, elevated transaminases, NAFLD, and fibrosis. Significant weight reduction was observed within first year after surgery, was slower in the second year, and stabilized within third year. Remarkable improvement followed in biological markers of metabolic syndrome. Ninety-six percent of initial liver biopsies had steatosis; 16% developed steatohepatitis and mild perivenular fibrosis. Significant improvement of the degenerative and inflammatory hepatic lesions in repeated biopsies and liver function readings was noted within 8 months after surgery. Obesity is a major and independent risk factor for the metabolic syndrome, NAFLD, NASH, and fibrosis. Surgical treatment improves metabolic abnormalities and hepatic lesions in long-term observations.

Idiosyncratic liver injury: challenges and approaches

Clinical presentations of drug-induced liver injury (DILI) cover essentially the entire spectrum of known liver diseases. However, in the last 8 years the form of liver injury that has most frequently resulted in labeling restrictions is idiosyncratic hepatocellular injury leading to acute liver failure. This rare form of DILI has a characteristic clinical presentation that includes an acute onset after uneventful treatment with drug for weeks to months. Serum alanine aminotransferase rises to very high levels and the appearance of jaundice indicates a high mortality even if the therapy is discontinued. Drugs that can cause this type of injury almost always are associated with frequent (2-15% of all treated patients) and minor serum aminotransferase elevations. These elevations are believed to reflect true liver injury, but often reverse even if drug therapy is continued. The bases for this "adaptation" is not known, as is why some patients do not adapt and develop progressive liver injury. Understanding how drugs cause severe idiosyncratic hepatocellular toxicity has been frustrated by the lack of good preclinical models. Indeed, because these events occur so rarely, the vast majority of humans are not good models. Studies of genomic DNA from affected individuals should provide important insight but not the complete answer because environmental factors almost certainly contribute to individual susceptibility. The most fruitful approach may therefore lie in focused and well-controlled phenotype/genotype studies of the rare patients who have survived this type of injury. The National Institute of Diabetes and Digestive and Kidney Diseases of The National Institutes of Health has recently sponsored a cooperative agreement (UO1) to create a Drug Induced Liver Injury Network (DILIN). DILIN consists of University of Michigan, Indiana University, University of Connecticut, University of California, San Francisco, University of North Carolina, and Duke University. This network should provide heretofore missing resources required to address the problem.

Prevention and treatment of the metabolic syndrome

The prevalence of the metabolic syndrome is increasing owing to lifestyle changes leading to obesity. This syndrome is a complex association of several interrelated abnormalities that increase the risk for cardiovascular disease and progression to diabetes mellitus (DM). Insulin resistance is the key factor for the clustering of risk factors characterizing the metabolic syndrome. The National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III defined the criteria for the diagnosis of the metabolic syndrome and established the basic principles for its management. According to these guidelines, treatment involves the improvement of the underlying insulin resistance through lifestyle modification (eg, weight reduction and increased physical activity) and possibly by drugs. The coexistent risk factors (mainly dyslipidemia and hypertension) should also be addressed. Since the main goal of lipid-lowering treatment is to achieve the NCEP low-density lipoprotein cholesterol (LDL-C) target, statins are a good option. However, fibrates (as monotherapy or in combination with statins) are useful for the treatment of the metabolic syndrome that is commonly associated with hypertriglyceridemia and decreased high-density lipoprotein cholesterol (HDL-C) levels. The blood pressure target is < 140/90 mm Hg. The effect on carbohydrate homeostasis should possibly be taken into account in selecting an antihypertensive drug. Patients with the metabolic syndrome commonly have other less well-defined metabolic abnormalities (eg, hyperuricemia and raised C-reactive protein levels) that may also be associated with an increased cardiovascular risk. It seems appropriate to manage these abnormalities. Drugs that beneficially affect carbohydrate metabolism and delay or even prevent the onset of DM (eg, thiazolidinediones or acarbose) could be useful in patients with the metabolic syndrome. Furthermore, among the more speculative benefits of treatment are improved liver function in nonalcoholic fatty liver disease and a reduction in the risk of acute gout.

Glitazones and the management of insulin resistance: what they do and how might they be used

Thiazolidinediones (glitazones) are the only compounds currently available that specifically target tissue insulin resistance. The two currently available drugs in this class, pioglitazone and rosiglitazone,are approved by the Food and Drug Administration for the treatment of type 2 diabetes mellitus only. The therapeutic potential of the glitazones for other consequences of insulin resistance has stirred considerable interest, especially with regard to their potential beneficial impact on atherosclerotic cardiovascular disease and diabetes prevention. They also have been considered in the management of polycystic ovarian syndrome, nonalcoholic fatty liver disease, and other consequences of insulin resistance. The nonglycemic potential of glitazones is a clinical area in rapid evolution, wherein most data are on the impact of the glitazones onsurrogate markers that are associated with diseases, not on disease outcomes. This article provides insight and guidance to clinicians on the diverse nonglycemic potential of glitazones until conclusive outcome data become available.