Fibroblast growth factor 21 is an early predictor of acute-on-chronic liver failure in critically ill patients with cirrhosis

Mitochondrial dysfunction affects hepatic immune and metabolic remodeling in patients with hepatitis B virus-related acute-on-chronic liver failure

BACKGROUND

Immune dysregulation and metabolic derangement have been recognized as key factors that contribute to the progression of hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF). However, the mechanisms underlying immune and metabolic derangement in patients with advanced HBV-ACLF are unclear.

AIM

To identify the bioenergetic alterations in the liver of patients with HBV-ACLF causing hepatic immune dysregulation and metabolic disorders.

METHODS

Liver samples were collected from 16 healthy donors (HDs) and 17 advanced HBV-ACLF patients who were eligible for liver transplantation. The mitochondrial ultrastructure, metabolic characteristics, and immune microenvironment of the liver were assessed. More focus was given to organic acid metabolism as well as the function and subpopulations of macrophages in patients with HBV-ACLF.

RESULTS

Compared with HDs, there was extensive hepatocyte necrosis, immune cell infiltration, and ductular reaction in patients with ACLF. In patients, the liver suffered severe hypoxia, as evidenced by increased expression of hypoxia-inducible factor-1α. Swollen mitochondria and cristae were observed in the liver of patients. The number, length, width, and area of mitochondria were adaptively increased in hepatocytes. Targeted metabolomics analysis revealed that mitochondrial oxidative phosphorylation decreased, while anaerobic glycolysis was enhanced in patients with HBV-ACLF. These findings suggested that, to a greater extent, hepa-tocytes used the extra-mitochondrial glycolytic pathway as an energy source. Patients with HBV-ACLF had elevated levels of chemokine C-C motif ligand 2 in the liver homogenate, which stimulates peripheral monocyte infiltration into the liver. Characterization and functional analysis of macrophage subsets revealed that patients with ACLF had a high abundance of CD68+ HLA-DR+ macrophages and elevated levels of both interleukin-1β and transforming growth factor-β1 in their livers. The abundance of CD206+ CD163+ macrophages and expression of interleukin-10 decreased. The correlation analysis revealed that hepatic organic acid metabolites were closely associated with macrophage-derived cytokines/chemokines.

CONCLUSION

The results indicated that bioenergetic alteration driven by hypoxia and mitochondrial dysfunction affects hepatic immune and metabolic remodeling, leading to advanced HBV-ACLF. These findings highlight a new therapeutic target for improving the treatment of HBV-ACLF.

Interleukin-8 predicts short-term mortality in acute-on-chronic liver failure patients with hepatitis B-related-related cirrhosis background

BACKGROUND

Acute-on-chronic liver failure (ACLF) is a distinctive and severe syndrome, marked by an excessive systemic inflammatory response. In vivo, interleukin 8 (IL-8) is an essential pro-inflammatory cytokine. We aimed to investigate the value of serum IL-8 levels in predicting mortality in ACLF patients in the background of hepatitis B virus-related cirrhosis.

METHODS

In this study, we conducted a retrospective analysis of the clinical baseline characteristics of 276 patients with ACLF in the context of HBV-related cirrhosis. Logistic regression analysis was employed to identify independent risk factors for short-, intermediate-, and long-term mortality. Using these independent risk factors, we developed a nomogram model, which was subsequently validated. To assess the clinical usefulness of the nomogram model, we performed decision curve analysis (DCA).

RESULTS

Out of the 276 patients with ACLF, 98 (35.5%), 113 (40.9%), and 128 (46.4%) died within 28, 90, and 180 days, respectively. Serum IL-8 levels were only an independent predictor of 28-day mortality and could simply classify ACLF patients. Conversely, mean arterial pressure (MAP), HBV-DNA, and COSHACLF IIs were independent predictors of mortality across all three observation periods. We constructed a nomogram based on IL-8 that was able to visualise and predict 28-day mortality with a C-index of 0.901 (95% CI: 0.862-0.940). Our calibration curves, Predicted Probability of Death & Actual Survival Status plot, and Confusion Matrix demonstrated the nomogram model's strong predictive power. DCA indicated the nomogram's promising clinical utility in predicting 28-day mortality in ACLF patients.

CONCLUSION

Serum IL-8 levels predict short-term mortality in ACLF patients in the background of HBV-associated cirrhosis, and the developed Nomogram model has strong predictive power and good clinical utility.

Binge drinking episode causes acute, specific alterations in systemic and hepatic inflammation-related markers

BACKGROUND

Frequent binge drinking is a known contributor to alcohol-related harm, but its impact on systemic and hepatic inflammation is not fully understood. We hypothesize that changes in immune markers play a central role in adverse effects of acute alcohol intake, especially in patients with early liver disease.

AIM

To investigate the effects of acute alcohol intoxication on inflammation-related markers in hepatic and systemic venous plasma in people with alcohol-related liver disease (ArLD), non-alcoholic fatty liver disease (NAFLD) and healthy controls.

METHODS

Thirty-eight participants (13 with ArLD, 15 with NAFLD and 10 healthy controls) received 2.5 mL of 40% ethanol per kg body weight via a nasogastric tube. Seventy-two inflammation-related markers were quantified in plasma from hepatic and systemic venous blood, at baseline, 60 and 180 min after intervention.

RESULTS

Alcohol intervention altered the levels of 31 of 72 and 14 of 72 markers in the systemic and hepatic circulation. All changes observed in the hepatic circulation were also identified in the systemic circulation after 180 min. Only FGF21 and IL6 were increased after alcohol intervention, while the remaining 29 markers decreased. Differences in response to acute alcohol between the groups were observed for 8 markers, and FGF21 response was blunted in individuals with steatosis.

CONCLUSION

Acute alcohol intoxication induced changes in multiple inflammation-related markers, implicated in alcohol metabolism and hepatocellular damage. Differences identified between marker response to binge drinking in ArLD, NAFLD and healthy controls may provide important clues to disease mechanisms and potential targets for treatment.

CLINICAL TRIAL NUMBER

NCT03018990.

Fibroblast Growth Factor 21 in Chronic Hepatitis C: A Potential Non-Invasive Biomarker of Liver Status upon Viral Eradication

Fibroblast growth factor 21 (FGF-21), previously recognized as a marker of liver damage and a potential drug target in non-alcoholic fatty liver disease (NAFLD), has unclear implications in hepatitis C virus (HCV) infections. This study aimed to investigate the relationship between FGF-21 levels and liver health in patients with HCV undergoing direct-acting antiviral (DAA) treatment. Forty-five patients were assessed for liver stiffness, blood chemistry, and other relevant metrics before and after achieving sustained viral response (SVR), defined as the absence of detectable HCV-RNA after 24 weeks of treatment. Post-treatment, all patients showed a decrease in liver stiffness and improved liver enzyme levels (AST and ALT), alongside an increase in FGF-21 levels. Interestingly, the increase in FGF-21 correlated negatively with liver stiffness but showed no correlation with hepatic steatosis. The observed elevation in FGF-21 levels at SVR following DAA therapy for chronic HCV infection can be attributed to the restoration of hepatic function, including its synthetic capabilities. Specifically, the mitigation of liver fibrosis post-HCV eradication is expected to lead to improvements in liver function, such as enhanced albumin and FGF-21 production. This improvement in synthetic function likely drives the increase in FGF-21 levels, rather than changes in liver fat content. We suggest a potential role of FGF-21 as a marker of fibrosis and hepatic cytotoxicity and as a drug target beyond NAFLD, to be confirmed by additional studies.

The association of FGF-21 with the risk of newly diagnosed type-2 diabetes mellitus: a cross-sectional study in Southern China

BACKGROUND

This study investigated the relationship between fibroblast growth factor 21 (FGF-21) and newly diagnosed type-2 diabetes mellitus (T2DM).

METHODS

In this cross-sectional study, FGF-21 and T2DM risk were analyzed using restricted cubic splines with univariate or multivariate logistic regression analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated via logistic regression analysis. Cluster and subgroup analyses were conducted to evaluate the associations between FGF-21 and diabetes in different subpopulations. Nomograms and ROC curves were used to explore the clinical utility of FGF-21 in the diabetes assessment model.

RESULTS

High levels of FGF-21 were significantly associated with a high risk of T2DM after adjusting for confounding factors in both the total population and subpopulations (P for trend < 0.001). In the total population, the ORs of diabetes with increasing FGF-21 quartiles were 1.00 (reference), 1.24 (95% CI 0.56-2.80; quartile 2), 2.47 (95% CI 1.18-5.33; quartile 3), and 3.24 (95% CI 1.53-7.14; quartile 4) in Model 4 (P < 0.001), and the trend was consistent in different subpopulations. In addition, compared with the model constructed with conventional noninvasive indicators, the AUC of the model constructed by adding FGF-21 was increased from 0.668 (95% CI: 0.602-0.733) to 0.715 (95% CI: 0.654-0.777), indicating that FGF-21 could significantly improve the risk-assessment efficiency of type-2 diabetes.

CONCLUSION

This study demonstrated that a high level of circulating FGF-21 was positively correlated with diabetes, and levels of FGF-21 could be an important biomarker for the assessment of diabetes risk.

Myostatin is associated with the presence and development of acute-on-chronic liver failure

BACKGROUND & AIMS

Acute-on-chronic liver failure (ACLF) has been linked to different pathophysiological mechanisms, including systemic inflammation and mitochondrial dysfunction. Sarcopenia has also been proposed as a potential mechanism; myostatin is a key factor inducing sarcopenia. Therefore, this study aimed to evaluate the association of myostatin levels with the development of ACLF and mortality in patients with cirrhosis.

METHODS

We performed a prospective cohort study, including both outpatient and hospitalized patients with cirrhosis. Clinical, biochemical, and nutritional parameters were evaluated, and the development of acute decompensation (AD) or ACLF during follow-up was recorded. ACLF was defined according to the EASL-CLIF criteria. Receiver-operating characteristic, Kaplan-Meier and Cox regression analyses were performed.

RESULTS

A total of 186 patients with the whole spectrum of cirrhosis were included; mean age was 53.4 ± 14 years, mean Child-Pugh score was 8 ± 2.5 and mean MELD score was 15 ± 8. There was a stepwise decrease in myostatin levels from a compensated stage to AD and ACLF. Myostatin correlated positively with nutritional markers and negatively with severity scores. The prevalence of sarcopenia was 73.6%. During follow-up, 27.9% of patients developed AD and 25.8% developed ACLF. Most episodes were grade 2-3, mainly (62.5%) precipitated by infections. The most common organ failures observed were in the liver (63.3%) and the kidney (64.6%). Receiver-operating characteristic analysis yielded <1,280 pg/ml as the best serum myostatin cut-off for the prediction of ACLF. In Kaplan-Meier curves and multivariate analysis, myostatin levels remained independently associated with the incidence of ACLF and survival.

CONCLUSIONS

There is a progressive decrease in myostatin levels as cirrhosis progresses, demonstrating an association of sarcopenia with the development of ACLF and increased mortality.

IMPACT AND IMPLICATIONS

Myostatin is a muscle hormone, it is decreased in patients with muscle loss and is a marker of impaired muscle function. In this study we show that myostatin levels are decreased in patients with cirrhosis, with lower levels in patients with acute decompensation and acute-on chronic liver failure (ACLF). Low myostatin levels in cirrhosis predict the development of ACLF and mortality independently of liver disease severity and sex.

Meteorin-like protein overexpression ameliorates fulminant hepatitis in mice by inhibiting chemokine-dependent immune cell infiltration

Myokines, which are recently identified cytokines secreted by skeletal muscle in response to stimulation, are crucial for the maintenance of liver function. Fulminant hepatitis (FH) is a life-threatening pathological condition with severe hepatic dysfunction. In this study, we investigated the role of meteorin-like (METRNL), a new myokine, in the pathogenesis of FH. We compared serum samples and liver tissues from FH patients and healthy controls and found that hepatic and serum METRNL levels were significantly increased in FH patients, and serum METRNL levels were related to disease severity in FH patients. We then established a concanavalin A-induced FH model in METRNL-overexpressing and control mice. We found that hepatic METRNL levels in FH mice were significantly increased, and METRNL in the liver was mainly derived from macrophages. In the cultured mouse macrophage line (RAW264.7 cells) and mouse primary peritoneal macrophages (PMs), METRNL overexpression significantly inhibited the release of the proinflammatory cytokines TNF and IL-1β. In METRNL-overexpressing mice, concanavalin A-induced liver injury was significantly ameliorated. Moreover, METRNL overexpression significantly reduced chemokine-dependent inflammatory cell infiltration into the liver. METRNL overexpression also suppressed liver CD4+ T cell differentiation into Th 1 cells and inhibited the secretion of Th 1 cytokines. Taken together, these data suggest that METRNL overexpression effectively ameliorates FH. Therefore, METRNL may serve as a potential biomarker and therapeutic target for FH.

Effect of a collagen-enriched beverage with or without omega-3 fatty acids on wound healing, metabolic biomarkers, and adipokines in patients with major burns

BACKGROUND & AIMS

This study investigated the effects of collagen hydrolysate and omega-3 fatty acids (FAs) on the rate and quality of wound healing, metabolic disorders, and adipose-derived peptides in patients with major burns.

METHODS

In this randomized clinical trial, 66 patients with 20-45% deep partial or full-thickness burns were randomly assigned to three groups to receive either a beverage containing collagen (40 gr/d), collagen (40 gr/d) plus 3 gr/d omega-3 (ω-3) FAs, or placebo for four weeks. Wound healing rate, Vancouver scar scale (VSS), as well as baseline, weeks two and three serum concentrations of adiponectin, fibroblast growth factor 21 (FGF21), neuregulin 4 (NRG4), transforming growth factor (TGF)-β1, and pre-albumin/hs-CRP ratio were assessed.

RESULTS

The wound healing rate during the weeks post-burn (p = 0.006 and p = 0.01), and days of 95% (21.3 ± 6.8 and 22.9 ± 8.7 vs. 34.3 ± 14.8 days, p = 0.003 and p = 0.03) and complete (26 ± 7.7 and 27.4 ± 9.4 vs. 41.1 ± 16.6 days, p = 0.003 and p = 0.01) wound healing were significantly better with Collagen and Collagen. ω-3 compared to the placebo group. The VSS was significantly lower, indicated better scar status, in the both intervention groups compared to the placebo (p = 0.02 and p = 0.01). Wound healing outcomes were not statistically different between the Collagen and Collagen. ω-3 groups. Hs-CRP/pre-albumin ratio was significantly lower in the Collagen. ω-3 than the placebo group at week three (1.2 ± 1.9 vs. 4.8 ± 7.7 dl/l, p = 0.03). The significant decrease in serum adiponectin seen during the trial course within the placebo (10 ± 8.8 to 5.8 ± 4.9 mg/l, p = 0.03) and Collagen (11.8 ± 14 to 8.6 ± 11.7 mg/l, p = 0.03) groups was prevented in the Collagen. ω-3 group (p = 0.4). Circulating FGF21 decreased significantly within the Collagen (p = 0.005) and Collagen. ω-3 (p = 0.02) groups at the end of week three compared to the baseline.

CONCLUSIONS

Adding collagen hydrolysate as part of adjunctive therapy improved wound healing rate and quality. These findings as well as the efficacy of omega-3 FAs need to be further confirmed in larger populations. This study was registered with the Iranian Registry of Clinical Trials (IRCT20090901002394N42).

Localization of FGF21 Protein and Lipid Metabolism-Related Genes in Camels

With the ability to survive under drought and chronic hunger, camels display a unique regulation characteristic of lipid metabolism. Fibroblast growth factor (FGF) 21 is a peptide hormone that regulates metabolic pathways, especially lipid metabolism, which was considered as a promising therapeutic target for metabolic diseases. To understand the FGF21 expression pattern and its potential relationship with lipid metabolism in camels, this study investigated the distribution and expression of FGF21, receptor FGFR1, and two lipid metabolism markers, leptin and hormone-sensitive lipase (HSL), using an immunohistochemistry (IHC) assay. The results showed that FGF21 was widely expressed in camel central nerve tissue and peripheral organs but absent in lung and gametogenic tissue, including the testis, epididymis, and ovary. In striated muscle, FGF21 is only present at the fiber junction. FGFR1 is expressed in almost all tissues and cells, indicating that all tissues are responsive to FGF21 and other FGF-mediated signals. Leptin and HSL are mainly located in metabolic and energy-consuming organs. In the CNS, leptin and HSL showed a similar expression pattern with FGFR1. In addition, leptin expression is extremely high in the bronchial epithelium, which may be due to its role in the immune responses of respiratory mucosa, in addition to fat stores and energy balance. This study found that FGF21 showed active expression in the nervous system of camels, which may be related to the adaptability of camels to arid environments and the specific regulation of lipid metabolism. This study showed a special FGF21-mediated fat conversion pattern in camels and provides a reference for developing a potential therapeutic method for fat metabolism disease.

Research progress on short-term prognosis of acute-on-chronic liver failure

INTRODUCTION

Acute-on-chronic liver failure (ACLF) is a clinical syndrome characterized as a severe condition with rapid progression, poor therapeutic response and poor prognosis. Early and timely evaluation of the prognosis is helpful for providing appropriate clinical intervention and prolonging patient survival.

AREAS COVERED

Currently, there are no specific dynamic and comprehensive approaches to assess the prognosis of patients with ACLF. This article reviews the progress in evaluating the short-term prognosis of ACLF to provide future directions for more dynamic prospective large-scale multicenter studies and a basis for individualized and precise treatment for ACLF patients. We searched PubMed and Web of Science with the term 'acute on chronic liver failure' and 'prognosis.' There was no date or language restriction, and our final search was on 26 October 2022.

EXPERT OPINION

ACLF is a dynamic process, and the best prognostic marker is the clinical evolution of organ failure over time. New prognostic markers are developing not only in the fields of genetics and histology but also toward diversification combined with imaging. Determining which patients will benefit from continued advanced life support is a formidable challenge, and accurate short-term prognostic assessments of ACLF are a good approach to addressing this issue.

Emerging roles of fibroblast growth factor 21 in critical disease

In spite of the great progress in the management of critical diseases in recent years, its associated prevalence and mortality of multiple organ failure still remain high. As an endocrine hormone, fibroblast growth factor 21 (FGF21) functions to maintain homeostasis in the whole body. Recent studies have proved that FGF21 has promising potential effects in critical diseases. FGF21 has also been found to have a close relationship with the progression of critical diseases and has a great predictive function for organ failure. The level of FGF21 was elevated in both mouse models and human patients with sepsis or other critical illnesses. Moreover, it is a promising biomarker and has certain therapeutic roles in some critical diseases. We focus on the emerging roles of FGF21 and its potential effects in critical diseases including acute lung injury/acute respiratory distress syndrome (ALI/ARDS), acute myocardial injury (AMI), acute kidney injury (AKI), sepsis, and liver failure in this review. FGF21 has high application value and is worth further studying. Focusing on FGF21 may provide a new perspective for the management of the critical diseases.

Animal models applied to acute-on-chronic liver failure: Are new models required to understand the human condition?

The liver is a multifaceted organ; its location and detoxifying function expose this organ to countless injuries. Acute-on-chronic failure liver (ACLF) is a severe syndrome that affects the liver due to acute decompensation in patients with chronic liver disease. An infection environment, ascites, increased liver enzymes and prothrombin time, encephalopathy and fast-evolving multiorgan failure, leading to death, usually accompany this. The pathophysiology remains poorly understand. In this context, animal models become a very useful tool in this regard, as understanding; the disease may be helpful in developing novel therapeutic methodologies for ACLF. However, although animal models display several similarities to the human condition, they do not represent all ACLF manifestations, resulting in significant challenges. An initial liver cirrhosis framework followed by the induction of an acute decompensation by administering lipopolysaccharide and D-GaIN, potentiating liver damage supports the methodologies applied to induce experimental ACLF. The entire methodology has been described mostly for rats. Nevertheless, a quick PubMed database search indicates about 30 studies concerning ACFL models and over 1000 regarding acute liver failure models. These findings demonstrate the clear need to establish easily reproducible ACFL models to elucidate questions about this quickly established and often fatal syndrome.

Animal models applied to acute-on-chronic liver failure: Are new models required to understand the human condition?

The liver is a multifaceted organ; its location and detoxifying function expose this organ to countless injuries. Acute-on-chronic failure liver (ACLF) is a severe syndrome that affects the liver due to acute decompensation in patients with chronic liver disease. An infection environment, ascites, increased liver enzymes and prothrombin time, encephalopathy and fast-evolving multiorgan failure, leading to death, usually accompany this. The pathophysiology remains poorly understand. In this context, animal models become a very useful tool in this regard, as understanding; the disease may be helpful in developing novel therapeutic methodologies for ACLF. However, although animal models display several similarities to the human condition, they do not represent all ACLF manifestations, resulting in significant challenges. An initial liver cirrhosis framework followed by the induction of an acute decompensation by administering lipopolysaccharide and D-GaIN, potentiating liver damage supports the methodologies applied to induce experimental ACLF. The entire methodology has been described mostly for rats. Nevertheless, a quick PubMed database search indicates about 30 studies concerning ACFL models and over 1000 regarding acute liver failure models. These findings demonstrate the clear need to establish easily reproducible ACFL models to elucidate questions about this quickly established and often fatal syndrome.

FGF21 (Fibroblast Growth Factor 21) Defines a Potential Cardiohepatic Signaling Circuit in End-Stage Heart Failure

BACKGROUND

Extrinsic control of cardiomyocyte metabolism is poorly understood in heart failure (HF). FGF21 (Fibroblast growth factor 21), a hormonal regulator of metabolism produced mainly in the liver and adipose tissue, is a prime candidate for such signaling.

METHODS

To investigate this further, we examined blood and tissue obtained from human subjects with end-stage HF with reduced ejection fraction at the time of left ventricular assist device implantation and correlated serum FGF21 levels with cardiac gene expression, immunohistochemistry, and clinical parameters.

RESULTS

Circulating FGF21 levels were substantially elevated in HF with reduced ejection fraction, compared with healthy subjects (HF with reduced ejection fraction: 834.4 [95% CI, 628.4-1040.3] pg/mL, n=40; controls: 146.0 [86.3-205.7] pg/mL, n=20, P=1.9×10-5). There was clear FGF21 staining in diseased cardiomyocytes, and circulating FGF21 levels negatively correlated with the expression of cardiac genes involved in ketone metabolism, consistent with cardiac FGF21 signaling. FGF21 gene expression was very low in failing and nonfailing hearts, suggesting extracardiac production of the circulating hormone. Circulating FGF21 levels were correlated with BNP (B-type natriuretic peptide) and total bilirubin, markers of chronic cardiac and hepatic congestion.

CONCLUSIONS

Circulating FGF21 levels are elevated in HF with reduced ejection fraction and appear to bind to the heart. The liver is likely the main extracardiac source. This supports a model of hepatic FGF21 communication to diseased cardiomyocytes, defining a potential cardiohepatic signaling circuit in human HF.

Mitochondrial dysfunction governs immunometabolism in leukocytes of patients with acute-on-chronic liver failure

BACKGROUND & AIMS

Patients with acute-on-chronic liver failure (ACLF) present a systemic hyperinflammatory response associated with increased circulating levels of small-molecule metabolites. To investigate whether these alterations reflect inadequate cell energy output, we assessed mitochondrial morphology and central metabolic pathways with emphasis on the tricarboxylic acid (TCA) cycle in peripheral leukocytes from patients with acutely decompensated (AD) cirrhosis, with and without ACLF.

METHODS

The study included samples from patients with AD cirrhosis (108 without and 128 with ACLF) and 41 healthy individuals. Leukocyte mitochondrial ultrastructure was visualized by transmission electron microscopy and cytosolic and mitochondrial metabolic fluxes were determined by assessing NADH/FADH₂ production from various substrates. Plasma GDF15 and FGF21 were determined by Luminex and acylcarnitines by LC-MS/MS. Gene expression was analyzed by RNA-sequencing and PCR-based glucose metabolism profiler array.

RESULTS

Mitochondrial ultrastructure in patients with advanced cirrhosis was distinguished by cristae rarefication and swelling. The number of mitochondria per leukocyte was higher in patients, accompanied by a reduction in their size. Increased FGF21 and C6:0- and C8:0-carnitine predicted mortality whereas GDF15 strongly correlated with a gene set signature related to leukocyte activation. Metabolic flux analyses revealed increased energy production in mononuclear leukocytes from patients with preferential involvement of extra-mitochondrial pathways, supported by upregulated expression of genes encoding enzymes of the glycolytic and pentose phosphate pathways. In patients with ACLF, mitochondrial function analysis uncovered break-points in the TCA cycle at the isocitrate dehydrogenase and succinate dehydrogenase level, which were bridged by anaplerotic reactions involving glutaminolysis and nucleoside metabolism.

CONCLUSIONS

Our findings provide evidence at the cellular, organelle and biochemical levels that severe mitochondrial dysfunction governs immunometabolism in leukocytes from patients with AD cirrhosis and ACLF.

LAY SUMMARY

Patients at advanced stages of liver disease have dismal prognosis due to vital organ failures and the lack of treatment options. In this study, we report that the functioning of mitochondria, which are known as the cell powerhouse, is severely impaired in leukocytes of these patients, probably as a consequence of intense inflammation. Mitochondrial dysfunction is therefore a hallmark of advanced liver disease.

Fibroblast growth factor 21 attenuates iron overload-induced liver injury and fibrosis by inhibiting ferroptosis

Ferroptosis plays a role in several diseases such as iron overload-induced liver diseases. Manipulation of ferroptosis has been explored as a potential therapeutic strategy to treat related diseases. Numerous antioxidants have been identified to control ferroptosis but the cell-autonomous mechanisms responsible for regulating ferroptosis remain elusive. In the present study, we found that iron overload promoted ferroptosis in hepatocytes by excessively inducing HO-1 expression, which contributed to the progression of liver injury and fibrosis, accompanied by the upregulation of the FGF21 protein level in vitro and in vivo. Interestingly, both recombinant FGF21 and Fgf21 overexpression significantly protected against iron overload-induced hepatocytes mitochondria damage, liver injury and fibrosis by inhibiting ferroptosis. In contrast, the loss of FGF21 aggravated iron overload-induced ferroptosis. Notably, FGF21-induced HO-1 inhibition (via the promotion of HO-1 ubiquitination and degradation) and NRF2 activation provide a mechanistic explanation for this phenomenon. Taken together, we identified FGF21 as a novel ferroptosis suppressor. Thus, FGF21 activation may provide an effective strategy for the potential treatment of iron overload-induced ferroptosis-related diseases, such as hereditary haemochromatosis (HH).

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Iron overload robustly induces hepatic FGF21 expression both in vitro and in vivo.

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FGF21 suppresses iron overload-induced hepatocytes ferroptosis.

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Constitutive HO-1 activation contributes to iron overload-induced ferroptosis in hepatocytes.

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FGF21 protects hepatocytes from iron overload-induced ferroptosis by stimulating HO-1 ubiquitination and degradation.

Therapeutic targets, novel drugs, and delivery systems for diabetes associated NAFLD and liver fibrosis

Type 2 diabetes mellitus (T2DM) associated non-alcoholic fatty liver disease (NAFLD) is the fourth-leading cause of death. Hyperglycemia induces various complications, including nephropathy, cirrhosis and eventually hepatocellular carcinoma (HCC). There are several etiological factors leading to liver disease development, which involve insulin resistance and oxidative stress. Free fatty acid (FFA) accumulation in the liver exerts oxidative and endoplasmic reticulum (ER) stresses. Hepatocyte injury induces release of inflammatory cytokines from Kupffer cells (KCs), which are responsible for activating hepatic stellate cells (HSCs). In this review, we will discuss various molecular targets for treating chronic liver diseases, including homeostasis of FFA, lipid metabolism, and decrease in hepatocyte apoptosis, role of growth factors, and regulation of epithelial-to-mesenchymal transition (EMT) and HSC activation. This review will also critically assess different strategies to enhance drug delivery to different cell types. Targeting nanocarriers to specific liver cell types have the potential to increase efficacy and suppress off-target effects.

Multidimensional Biomarker Analysis Including Mitochondrial Stress Indicators for Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is accompanied by a complex and multifactorial pathogenesis with sequential progressions from inflammation to fibrosis and then to cancer. This heterogeneity interferes with the development of precise diagnostic and prognostic strategies for NAFLD. The current approach for the diagnosis of simple steatosis, steatohepatitis, and cirrhosis mainly consists of ultrasonography, magnetic resonance imaging, elastography, and various serological analyses. However, individual dry and wet biomarkers have limitations demanding an integrative approach for the assessment of disease progression. Here, we review diagnostic strategies for simple steatosis, steatohepatitis and hepatic fibrosis, followed by potential biomarkers associated with fat accumulation and mitochondrial stress. For mitochondrial stress indicators, we focused on fibroblast growth factor 21 (FGF21), growth differentiation factor 15 (GDF15), angiopoietin-related growth factor and mitochondrial-derived peptides. Each biomarker may not strongly indicate the severity of steatosis or steatohepatitis. Instead, multidimensional analysis of different groups of biomarkers based on pathogenic mechanisms may provide decisive diagnostic/prognostic information to develop a therapeutic plan for patients with NAFLD. For this purpose, mitochondrial stress indicators, such as FGF21 or GDF15, could be an important component in the multiplexed and contextual interpretation of NAFLD. Further validation of the integrative evaluation of mitochondrial stress indicators combined with other biomarkers is needed in the diagnosis/prognosis of NAFLD.

Fibroblast Growth Factor 21 Response in a Preclinical Alcohol Model of Acute-on-Chronic Liver Injury

BACKGROUND AND AIMS

Fibroblast growth factor (FGF) 21 has recently been shown to play a potential role in bile acid metabolism. We aimed to investigate the FGF21 response in an ethanol-induced acute-on-chronic liver injury (ACLI) model in Abcb4-/- mice with deficiency of the hepatobiliary phospholipid transporter.

METHODS

Total RNA was extracted from wild-type (WT, C57BL/6J) and Abcb4-/- (KO) mice, which were either fed a control diet (WT-Cont and KO-Cont groups; n = 28/group) or ethanol diet, followed by an acute ethanol binge (WT-EtOH and KO-EtOH groups; n = 28/group). A total of 58 human subjects were recruited into the study, including patients with alcohol-associated liver disease (AALD; n = 31) and healthy controls (n = 27). The hepatic and ileal expressions of genes involved in bile acid metabolism, plasma FGF levels, and bile acid and its precursors 7α- and 27-hydroxycholesterol (7α- and 27-OHC) concentrations were determined. Primary mouse hepatocytes were isolated for cell culture experiments.

RESULTS

Alcohol feeding significantly induced plasma FGF21 and decreased hepatic Cyp7a1 levels. Hepatic expression levels of Fibroblast growth factor receptor 1 (Fgfr1), Fgfr4, Farnesoid X-activated receptor (Fxr), and Small heterodimer partner (Shp) and plasma FGF15/FGF19 levels did not differ with alcohol challenge. Exogenous FGF21 treatment suppressed Cyp7a1 in a dose-dependent manner in vitro. AALD patients showed markedly higher FGF21 and lower 7α-OHC plasma levels while FGF19 did not differ.

CONCLUSIONS

The simultaneous upregulation of FGF21 and downregulation of Cyp7a1 expressions upon chronic plus binge alcohol feeding together with the invariant plasma FGF15 and hepatic Shp and Fxr levels suggest the presence of a direct regulatory mechanism of FGF21 on bile acid homeostasis through inhibition of CYP7A1 by an FGF15-independent pathway in this ACLI model. Lay Summary: Alcohol challenge results in the upregulation of FGF21 and repression of Cyp7a1 expressions while circulating FGF15 and hepatic Shp and Fxr levels remain constant both in healthy and pre-injured livers, suggesting the presence of an alternative FGF15-independent regulatory mechanism of FGF21 on bile acid homeostasis through the inhibition of Cyp7a1.

Serum fibroblast growth factor 21 levels after out of hospital cardiac arrest are associated with neurological outcome

Fibroblast growth factor (FGF) 21 is a marker associated with mitochondrial and cellular stress. Cardiac arrest causes mitochondrial stress, and we tested if FGF 21 would reflect the severity of hypoxia-reperfusion injury after cardiac arrest. We measured serum concentrations of FGF 21 in 112 patients on ICU admission and 24, 48 and 72 h after out-of-hospital cardiac arrest with shockable initial rhythm included in the COMACARE study (NCT02698917). All patients received targeted temperature management for 24 h. We defined 6-month cerebral performance category 1–2 as good and 3–5 as poor neurological outcome. We used samples from 40 non-critically ill emergency room patients as controls. We assessed group differences with the Mann Whitney U test and temporal differences with linear modeling with restricted maximum likelihood estimation. We used multivariate logistic regression to assess the independent predictive value of FGF 21 concentration for neurologic outcome. The median (inter-quartile range, IQR) FGF 21 concentration was 0.25 (0.094–0.91) ng/ml in controls, 0.79 (0.37–1.6) ng/ml in patients at ICU admission (P < 0.001 compared to controls) and peaked at 48 h [1.2 (0.46–2.5) ng/ml]. We found no association between arterial blood oxygen partial pressure and FGF 21 concentrations. We observed with linear modeling an effect of sample timepoint (F 5.6, P < 0.01), poor neurological outcome (F 6.1, P = 0.01), and their interaction (F 3.0, P = 0.03), on FGF 21 concentration. In multivariate logistic regression analysis, adjusting for relevant clinical covariates, higher average FGF 21 concentration during the first 72 h was independently associated with poor neurological outcome (odds ratio 1.60, 95% confidence interval 1.10–2.32). We conclude that post cardiac arrest patients experience cellular and mitochondrial stress, reflected as a systemic FGF 21 response. This response is higher with a more severe hypoxic injury but it is not exacerbated by hyperoxia.

Current understanding and controversies on the clinical implications of fibroblast growth factor 21

Metabolic functions of the hepatic hormone fibroblast growth factor 21 (FGF21) have been recognized for more than a decade in studying the responses of human subjects and rodent models to nutritional stresses such as fasting, high-fat diet or ketogenic diet consumption, and ethanol intake. Our interest in the beneficial metabolic effects of FGF21 has risen due to its potential ability to serve as a therapeutic agent for various metabolic disorders, including type 2 diabetes, obesity, and fatty liver diseases, as well as its potential to act as a diagnostic or prognostic biomarker for metabolic and other disorders. Here, we briefly review the FGF21 gene and protein structures, its expression pattern, and cellular signaling cascades that mediate FGF21 production and function. We mainly focus on discussing experimental and clinical literature pertaining to FGF21 as a therapeutic agent. Furthermore, we present several lines of investigation, including a few studies conducted by our team, suggesting that FGF21 expression and function can be regulated by dietary polyphenol interventions. Finally, we discuss the literature debating FGF21 as a potential biomarker in various disorders.

Elevated neopterin levels are associated with acute-on-chronic liver failure and mortality in patients with liver cirrhosis

BACKGROUND

Macrophage activation plays a central role in hepatic and systemic inflammation and is involved in the pathogenesis of acute-on-chronic liver failure (ACLF).

AIMS

This study aimed to investigate neopterin levels in patients admitted for acute decompensation (AD) of cirrhosis, evaluating its relationship with ACLF and prognosis.

METHODS

This prospective cohort study included 205 adult subjects hospitalized for AD of cirrhosis. Twenty-one healthy subjects and 89 patients with stable cirrhosis were evaluated as controls.

RESULTS

Circulating neopterin was higher in AD as compared to stable cirrhosis and healthy controls (p<0.001). ACLF was independently associated with higher neopterin levels (OR 1.015, 95% CI 1.002-1.028, p = 0.025). In the multivariate Cox regression analysis, neopterin levels (HR = 1.002, IC 95% 1.000-1.004, p = 0.041), Child-Pugh class C, and ACLF were predictors of 30-day survival. Among patients with ACLF, the Kaplan-Meier survival probability was 71.4% in those with neopterin levels < 25 nmol/L and 31.0% if neopterin ≥ 25 nmol/L (p<0.001).

CONCLUSIONS

Higher circulating neopterin was associated with ACLF in patients hospitalized for AD of cirrhosis. Neopterin levels were also independently predictors of high short-term mortality, especially among patients with ACLF, and could represent a useful biomarker of macrophage activation in clinical practice.

Oxidative Phosphorylation Dysfunction Modifies the Cell Secretome

Mitochondrial oxidative phosphorylation disorders are extremely heterogeneous conditions. Their clinical and genetic variability makes the identification of reliable and specific biomarkers very challenging. Until now, only a few studies have focused on the effect of a defective oxidative phosphorylation functioning on the cell’s secretome, although it could be a promising approach for the identification and pre-selection of potential circulating biomarkers for mitochondrial diseases. Here, we review the insights obtained from secretome studies with regard to oxidative phosphorylation dysfunction, and the biomarkers that appear, so far, to be promising to identify mitochondrial diseases. We propose two new biomarkers to be taken into account in future diagnostic trials.

Precipitants of Acute-on-Chronic Liver Failure: An Opportunity for Preventative Measures to Improve Outcomes

Acute-on-chronic liver failure (ACLF) is a feared complication that can develop at any stage of chronic liver disease. The incidence of ACLF is increasing, leading to a significant burden to both the affected individual and health care systems. To date, our understanding of ACLF suggests that it may be initiated by precipitants such as systemic infection, alcohol use, or viral hepatitis. The prevalence of these vary significantly by geography and underlying liver disease, and these precipitants have a varying impact on patient prognosis. Herein, we present a review of our current understanding of the precipitants of ACLF, including gaps in current data and opportunities for meaningful intervention and areas of future research.

Fibroblast growth factor 21 is independently associated with severe hepatic steatosis in non-obese HIV-infected patients

BACKGROUND

Severe hepatic steatosis shows a high prevalence and contributes to morbidity and mortality in human immunodeficiency virus (HIV) infected patients. Known risk factors include obesity, dyslipidaemia and features of metabolic syndrome. Fibroblast growth factor 21 (FGF-21) is involved with hepatic glucose and lipid metabolism. This study aimed to evaluate FGF-21 as a biomarker for severe hepatic steatosis in non-obese HIV-infected patients.

METHODS

This is a prospective, cross-sectional, monocentric study including HIV-infected out-patients. Hepatic steatosis was measured via controlled attenuation parameter (CAP) using FibroScan 502 touch (ECHOSENS, France). Severe hepatic steatosis was defined at CAP ≥ 253 dB/m. Peripheral blood samples were collected and plasma was analysed for FGF-21. Demographic and clinical characteristics were collected from patient's health records.

RESULTS

In total, 73 non-obese HIV-monoinfected patients were included in this study. Prevalence of severe hepatic steatosis was 41%. Patients with severe hepatic steatosis showed significantly higher levels of FGF-21. Univariate analysis revealed FGF-21, BMI, hyperlipidaemia, ALT levels and arterial hypertension as significant, while multivariate analysis showed only FGF-21, arterial hypertension and ALT levels as significant independent risk factors for severe hepatic steatosis.

CONCLUSION

This study presents FGF-21 as an independent and stronger predictor of severe hepatic steatosis than blood lipids in HIV-infected patients. Moreover, arterial hypertension and ALT levels predict severe steatosis even in non-obese HIV-monoinfected patients. Furthermore, this study supports existing metabolic risk factors and expands them to non-obese HIV-infected patients.

Towards frailty biomarkers: Candidates from genes and pathways regulated in aging and age-related diseases

OBJECTIVE

Use of the frailty index to measure an accumulation of deficits has been proven a valuable method for identifying elderly people at risk for increased vulnerability, disease, injury, and mortality. However, complementary molecular frailty biomarkers or ideally biomarker panels have not yet been identified. We conducted a systematic search to identify biomarker candidates for a frailty biomarker panel.

METHODS

Gene expression databases were searched (http://genomics.senescence.info/genes including GenAge, AnAge, LongevityMap, CellAge, DrugAge, Digital Aging Atlas) to identify genes regulated in aging, longevity, and age-related diseases with a focus on secreted factors or molecules detectable in body fluids as potential frailty biomarkers. Factors broadly expressed, related to several "hallmark of aging" pathways as well as used or predicted as biomarkers in other disease settings, particularly age-related pathologies, were identified. This set of biomarkers was further expanded according to the expertise and experience of the authors. In the next step, biomarkers were assigned to six "hallmark of aging" pathways, namely (1) inflammation, (2) mitochondria and apoptosis, (3) calcium homeostasis, (4) fibrosis, (5) NMJ (neuromuscular junction) and neurons, (6) cytoskeleton and hormones, or (7) other principles and an extensive literature search was performed for each candidate to explore their potential and priority as frailty biomarkers.

RESULTS

A total of 44 markers were evaluated in the seven categories listed above, and 19 were awarded a high priority score, 22 identified as medium priority and three were low priority. In each category high and medium priority markers were identified.

CONCLUSION

Biomarker panels for frailty would be of high value and better than single markers. Based on our search we would propose a core panel of frailty biomarkers consisting of (1) CXCL10 (C-X-C motif chemokine ligand 10), IL-6 (interleukin 6), CX3CL1 (C-X3-C motif chemokine ligand 1), (2) GDF15 (growth differentiation factor 15), FNDC5 (fibronectin type III domain containing 5), vimentin (VIM), (3) regucalcin (RGN/SMP30), calreticulin, (4) PLAU (plasminogen activator, urokinase), AGT (angiotensinogen), (5) BDNF (brain derived neurotrophic factor), progranulin (PGRN), (6) α-klotho (KL), FGF23 (fibroblast growth factor 23), FGF21, leptin (LEP), (7) miRNA (micro Ribonucleic acid) panel (to be further defined), AHCY (adenosylhomocysteinase) and KRT18 (keratin 18). An expanded panel would also include (1) pentraxin (PTX3), sVCAM/ICAM (soluble vascular cell adhesion molecule 1/Intercellular adhesion molecule 1), defensin α, (2) APP (amyloid beta precursor protein), LDH (lactate dehydrogenase), (3) S100B (S100 calcium binding protein B), (4) TGFβ (transforming growth factor beta), PAI-1 (plasminogen activator inhibitor 1), TGM2 (transglutaminase 2), (5) sRAGE (soluble receptor for advanced glycosylation end products), HMGB1 (high mobility group box 1), C3/C1Q (complement factor 3/1Q), ST2 (Interleukin 1 receptor like 1), agrin (AGRN), (6) IGF-1 (insulin-like growth factor 1), resistin (RETN), adiponectin (ADIPOQ), ghrelin (GHRL), growth hormone (GH), (7) microparticle panel (to be further defined), GpnmB (glycoprotein nonmetastatic melanoma protein B) and lactoferrin (LTF). We believe that these predicted panels need to be experimentally explored in animal models and frail cohorts in order to ascertain their diagnostic, prognostic and therapeutic potential.