Serum metabolites detect the presence of advanced fibrosis in derivation and validation cohorts of patients with non-alcoholic fatty liver disease

Mechanistic Study of the Deuterium Effect in Chromatographic Separation for Chemical-Tagging Metabolomics and Its Application to Biomarker Discovery in Metabolic Dysfunction-Associated Steatohepatitis

Over the past decade, numerous metabolomics techniques have been developed using liquid chromatography-mass spectrometry (LC-MS). These methodologies have yielded significant findings and facilitated the identification of biomarkers. Among these, chemical-tagging methodologies combined with isotope surrogate tags have garnered considerable attention as a leading approach. Chemical-tagging reduces labor and costs by eliminating the need for internal standard preparation. However, the chromatographic deuterium effect (CDE) has persisted as a significant challenge. CDE poses a risk of data misinterpretation in metabolomics due to potential differences in matrix effects. Although the CDE mechanism has been partially elucidated, it has primarily been attributed to differences in hydrophobicity. A detailed understanding of CDE mechanisms would be valuable for designing chemical tags and optimizing liquid chromatography (LC) conditions. Moreover, emphasizing the CDE could aid in the separation and purification of deuterated compounds. In this study, we investigated the mechanistic basis of the CDE. Initially, four chromatography columns with different separation modes─octadecyl, octadecyl with a positively charged surface, biphenyl, and pentafluorophenyl (PFP) groups─were evaluated based on retention differences between 1H- and 2H6-labeled chemically tagged metabolites. Among these, the PFP column demonstrated the most effective reduction of the CDE, suggesting that electronic interactions with fluorine stabilized 2H-labeled metabolites. Further optimization using the PFP column showed its efficacy in reducing the level of CDE in human serum samples. Finally, the optimized approach was successfully applied to global metabolomics analysis of serum from a mouse model of metabolic dysfunction-associated steatohepatitis.

Multiomics Analysis of Liver Molecular Dysregulation Leading to Nonviral-Related Hepatocellular Carcinoma Development

Chronic liver diseases exhibit diverse backgrounds, and it is believed that numerous factors contribute to progression to cancer. To achieve effective prevention of nonviral hepatocellular carcinoma, it is imperative to identify fundamental molecular abnormalities at the patient level. Utilizing cancer-adjacent liver tissues obtained from hepatocellular carcinoma patients (chronic liver disease), we conducted RNA-Seq and metabolome analyses. In the chronic liver disease cohort, upregulation of inflammation-associated signals was observed, concomitant with accumulation of acylcarnitine and fatty acid and depletion of NADP+, gamma-tocopherol, and dehydroisoandrosterone-3-sulfate-1 (DHEAS). To minimize heterogeneity, we performed multiomics clustering, successfully categorizing the chronic liver disease cases into two distinct subtypes. Subtype 1 demonstrated elevated inflammatory levels, whereas Subtype 2 included a disproportionately high proportion of elderly cases. Furthermore, RNA-Seq analysis revealed upregulation of inflammatory signals in Subtype 1, while both subtypes exhibited downregulation of fatty acid metabolism. Metabolome analysis indicated a tendency of increased acylcarnitine levels in Subtype 1 and augmented fatty acid accumulation in Subtype 2. Validation of differentially expressed genes using the Gene Expression Omnibus (GEO) data set revealed the potential for amelioration through supplementation with antioxidants such as epigallocatechin gallate (EGCG).

Unraveling Metabolic Dysfunction-Associated Steatotic Liver Disease Through the Use of Omics Technologies

Non-alcoholic fatty liver disease (NAFLD), now referred to as metabolic dysfunction-associated steatotic liver disease (MASLD), is the most prevalent liver disorder globally, linked to obesity, type 2 diabetes, and cardiovascular risk. Understanding its potential progression from simple steatosis to cirrhosis and hepatocellular carcinoma (HCC) is crucial for patient management and treatment strategies. The disease's complexity requires innovative approaches for early detection and personalized care. Omics technologies-such as genomics, transcriptomics, proteomics, metabolomics, and exposomics-are revolutionizing the study of MASLD. These high-throughput techniques allow for a deeper exploration of the molecular mechanisms driving disease progression. Genomics can identify genetic predispositions, whilst transcriptomics and proteomics reveal changes in gene expression and protein profiles during disease evolution. Metabolomics offers insights into the metabolic alterations associated with MASLD, while exposomics links environmental exposures to MASLD progression and pathology. By integrating data from various omics platforms, researchers can map out the intricate biochemical pathways involved in liver disease progression. This review discusses the roles of omics technologies in enhancing the understanding of disease progression and highlights potential diagnostic and therapeutic targets within the MASLD spectrum, emphasizing the need for non-invasive tools in disease staging and treatment development.

Exploring Biomarkers in Nonalcoholic Fatty Liver Disease Among Individuals With Type 2 Diabetes Mellitus

Integrating biomarkers into a comprehensive strategy is crucial for precise patient management, especially considering the significant healthcare costs associated with diseases. Current studies emphasize the urgent need for a paradigm shift in conceptualizing nonalcoholic fatty liver disease (NAFLD), now renamed metabolic dysfunction-associated steatotic liver disease (MASLD). Biomarkers are emerging as indispensable tools for accurate diagnosis, risk stratification, and monitoring disease progression. This review classifies biomarkers into conventional and novel categories, such as lipids, insulin resistance, hepatic function, and cutting-edge imaging/omics, and evaluates their potential to transform the approach to MASLD among individuals with type 2 diabetes mellitus (T2D). It focuses on the critical role of biomarkers in early MASLD detection, enhancing predictive accuracy, and discerning responses to interventions (pharmacological or lifestyle modifications). Amid this discussion, the complexities of the relationship between T2D and MASLD are explored, considering factors like age, gender, genetics, ethnicity, and socioeconomic background. Biomarkers enhance the effectiveness of interventions and support global initiatives to reduce the burden of MASLD, thereby improving public health outcomes. This review recognizes the promising potential of biomarkers for diagnostic precision while candidly addressing the challenges in implementing these advancements in clinical practice. The transformative role of biomarkers emerges as a central theme, promising to reshape our understanding of disease trajectories, prognosis, and the customization of personalized therapeutic strategies for improved patient outcomes. From a future perspective, identifying early-stage biomarkers, understanding environmental impact through exposomes, and applying a multiomics approach may reveal additional insight into MASLD development.

Metabolomics at the cutting edge of risk prediction of MASLD

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major public health threat globally. Management of patients afflicted with MASLD and research in this domain are limited by the lack of robust well-established non-invasive biomarkers for diagnosis, prognostication, and monitoring. The circulating metabolome reflects both the systemic metabo-inflammatory milieu and changes in the liver in affected individuals. In this review we summarize the available literature on changes in the different components of the metabolome in MASLD with a focus on changes that are linked to the presence of underlying steatohepatitis, severity of disease activity, and fibrosis stage. We further summarize the existing literature around biomarker panels that are derived from interrogation of the metabolome. Their relevance to disease biology and utility in practice are also discussed. We further highlight potential direction for future studies particularly to ensure they are fit for purpose and suitable for widespread use.

Diagnostics and omics technologies for the detection and prediction of metabolic dysfunction-associated steatotic liver disease-related malignancies

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) continues to rise, making it the leading etiology of chronic liver diseases and a prime cause of liver-related mortality. MASLD can progress into steatohepatitis (termed MASH), fibrosis, cirrhosis, and ultimately cancer. MASLD is associated with increased risks of hepatocellular carcinoma (HCC) and also extrahepatic malignancies, which can develop in both cirrhotic and non-cirrhotic patients, emphasizing the importance of identifying patients with MASLD at risk of developing MASLD-associated malignancies. However, the optimal screening, diagnostic, and risk stratification strategies for patients with MASLD at risk of cancer are still under debate. Individuals with MASH-associated cirrhosis are recommended to undergo surveillance for HCC (e.g. by ultrasound and biomarkers) every six months. No specific screening approaches for MASLD-related malignancies in non-cirrhotic cases are established to date. The rapidly developing omics technologies, including genetics, metabolomics, and proteomics, show great potential for discovering non-invasive markers to fulfill this unmet need. This review provides an overview on the incidence and mortality of MASLD-associated malignancies, current strategies for HCC screening, surveillance and diagnosis in patients with MASLD, and the evolving role of omics technologies in the discovery of non-invasive markers for the prediction and risk stratification of MASLD-associated HCC.

Noninvasive tools for the assessment of fibrosis in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously nonalcoholic fatty liver disease (NAFLD), is the number one chronic liver disorder worldwide. Progression to advanced fibrosis marks the emergence of a significant risk of liver-related negative outcomes. However, only a minority of patients will present at this stage. Since widespread liver biopsy in unfeasible at such high disease prevalence, there was a need to develop noninvasive tests (NITs) that could easily and reliably be applied to patients with MASLD, regardless of clinical setting. The NITs include simple scores, like the fibrosis-4 (FIB-4) Index, patented serum tests, like the Enhanced Liver Fibrosis test (ELF™), and imaging-based modalities, like the vibration-controlled transient elastography (VCTE). Guidelines suggests a stepwise approach that utilizes more than one NIT, with FIB-4 <1.30 being used as a first step to rule out patients that do not need further testing. Subsequent choice of NIT will be influenced by setting, cost, and local availability. While these NITs are accurate, they are not perfect. As such, research is ongoing. A promising avenue is that of omics, a group of technologies that provide concomitant results on a large number of molecules (and other variables). With the advance of artificial intelligence, new NITs may arise from large demographic, biochemical, and radiological data sets.

The rate of muscle wasting in liver transplant recipients on waiting list: post-transplant outcomes and associated serum metabolite patterns

Background

Sarcopenia at the time of liver transplantation (LT) is an established risk factor for mortality following LT. However, most studies in this context have defined sarcopenia by one-time, static measurements. The aims of this study were (I) to determine the impact of the rate of muscle loss in waitlisted LT recipients on post-LT outcomes and (II) to identify patterns of serum metabolites associated with patients with more progressive sarcopenia.

Methods

Patients undergoing liver transplant from 2008 to 2018 who received more than one computed tomography (CT) scans within 12 months prior to liver transplant were included (n=61). The psoas muscle index (PMI) was calculated using Slice-O-Matic software and corrected for patient height (m2). Patients were classified into two groups based the rate of reduction in PMI-high wasting [HW; change in PMI (ΔPMI) ≤-1%/month] and low wasting (LW; ΔPMI >-1%/month). Pre-transplant serum metabolic profiles were collected using nuclear magnetic resonance (NMR) spectroscopy. Living kidney donor sera was used as healthy controls.

Results

Median ΔPMI was -2.0%/month in HW and -0.15%/month in LW patients (P<0.001). Post-transplant 1-year mortality was significantly higher in HW patients. There were no significant differences in metabolite concentrations between HW and LW patients. However, perturbations in taurine, sarcosine, betaine and the aromatic amino acids (AAAs), were observed in patients with liver disease as compared to healthy controls. Liver disease was also associated with a decrease in lipoprotein profiles, especially high-density lipoprotein (HDL) particles.

Conclusions

In patients undergoing LT, the rate of progression of sarcopenia is a strong prognostic indicator of post-LT death. Serum metabolite profiles were not characteristically unique to HW patients, and most closely resemble derangements associated with chronic liver disease.

Non-invasive Scores and Serum Biomarkers for Fatty Liver in the Era of Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD): A Comprehensive Review From NAFLD to MAFLD and MASLD

PURPOSE OF REVIEW

The prevalence of non-alcoholic fatty liver disease (NAFLD) is rapidly increasing worldwide, making it the leading cause of liver related morbidity and mortality. Currently, liver biopsy is the gold standard for assessing individuals with steatohepatitis and fibrosis. However, its invasiveness, sampling variability, and impracticality for large-scale screening has driven the search for non-invasive methods for early diagnosis and staging. In this review, we comprehensively summarise the evidence on the diagnostic performance and limitations of existing non-invasive serum biomarkers and scores in the diagnosis and evaluation of steatosis, steatohepatitis, and fibrosis.

RECENT FINDINGS

Several non-invasive serum biomarkers and scores have been developed over the last decade, although none has successfully been able to replace liver biopsy. The introduction of new NAFLD terminology, namely metabolic dysfunction-associated fatty liver disease (MAFLD) and more recently metabolic dysfunction-associated steatotic liver disease (MASLD), has initiated a debate on the interchangeability of these terminologies. Indeed, there is a need for more research on the variability of the performance of non-invasive serum biomarkers and scores across the diagnostic entities of NAFLD, MAFLD and MASLD. There remains a significant need for finding valid and reliable non-invasive methods for early diagnosis and assessment of steatohepatitis and fibrosis to facilitate prompt risk stratification and management to prevent disease progression and complications. Further exploration of the landscape of MASLD under the newly defined disease subtypes is warranted, with the need for more robust evidence to support the use of commonly used serum scores against the new MASLD criteria and validation of previously developed scores.

Metabolomics analysis of patients with Schistosoma japonicum infection based on UPLC-MS method

BACKGROUND

Schistosomiasis is still one of the most serious parasitic diseases. Evidence showed that the metabolite profile in serum can potentially act as a marker for parasitic disease diagnosis and evaluate disease progression and prognosis. However, the serum metabolome in patients with Schistosoma japonicum infection is not well defined. In this study, we investigated the metabolite profiles of patients with chronic and with advanced S. japonicum infection.

METHODS

The sera of 33 chronic S. japonicum patients, 15 patients with advanced schistosomiasis and 17 healthy volunteers were collected. Samples were extracted for metabolites and analyzed with ultra-performance liquid chromatography-mass spectrometry (UPLC-MS).

RESULTS

We observed significant differences in metabolite profiles in positive and negative ion modes between patients with advanced and chronic S. japonicum infection. In patients with chronic S. japonicum infection, 199 metabolites were significantly upregulated while 207 metabolites were downregulated in advanced infection. These differential metabolites were mainly concentrated in steroid hormone biosynthesis, cholesterol metabolism and bile secretion pathways. We also found that certain bile acid levels were significantly upregulated in the progression from chronic to advanced S. japonicum infection. In receiver operator characteristic (ROC) analysis, we identified three metabolites with area under the curve (AUC) > 0.8, including glycocholic (GCA), glycochenodeoxycholate (GCDCA) and taurochenodeoxycholic acid (TCDCA) concentrated in cholesterol metabolism, biliary secretion and primary bile acid biosynthesis.

CONCLUSIONS

This study provides evidence that GCA, GCDCA and TCDCA can potentially act as novel metabolite biomarkers to distinguish patients in different stages of S. japonicum infection. This study will contribute to the understanding of the metabolite mechanisms of the transition from chronic to advanced S. japonicum infection, although more studies are needed to validate this potential role and explore the underlying mechanisms.

Opportunities and barriers in omics-based biomarker discovery for steatotic liver diseases

The rising prevalence of liver diseases related to obesity and excessive use of alcohol is fuelling an increasing demand for accurate biomarkers aimed at community screening, diagnosis of steatohepatitis and significant fibrosis, monitoring, prognostication and prediction of treatment efficacy. Breakthroughs in omics methodologies and the power of bioinformatics have created an excellent opportunity to apply technological advances to clinical needs, for instance in the development of precision biomarkers for personalised medicine. Via omics technologies, biological processes from the genes to circulating protein, as well as the microbiome - including bacteria, viruses and fungi, can be investigated on an axis. However, there are important barriers to omics-based biomarker discovery and validation, including the use of semi-quantitative measurements from untargeted platforms, which may exhibit high analytical, inter- and intra-individual variance. Standardising methods and the need to validate them across diverse populations presents a challenge, partly due to disease complexity and the dynamic nature of biomarker expression at different disease stages. Lack of validity causes lost opportunities when studies fail to provide the knowledge needed for regulatory approvals, all of which contributes to a delayed translation of these discoveries into clinical practice. While no omics-based biomarkers have matured to clinical implementation, the extent of data generated has enabled the hypothesis-free discovery of a plethora of candidate biomarkers that warrant further validation. To explore the many opportunities of omics technologies, hepatologists need detailed knowledge of commonalities and differences between the various omics layers, and both the barriers to and advantages of these approaches.

NMR-based metabolomic signature: An important tool for the diagnosis and study of pathogenesis of autoimmune hepatitis

BACKGROUND AND AIMS

Metabolomics is used to predict, diagnose, and monitor metabolic disorders but altered metabolomic signatures have also been reported in diverse diseases, including autoimmune disorders. However, the metabolomic profile in autoimmune hepatitis (AIH) has not been investigated in depth. Therefore, we investigated the metabolomic signature of AIH and its significance as a diagnostic and pathogenetic tool.

APPROACH AND RESULTS

Metabolites in plasma samples from 50 patients with AIH at diagnosis, 43 healthy controls, 72 patients with primary biliary cholangitis (PBC), 26 patients with metabolic dysfunction-associated liver disease, and 101 patients with chronic viral hepatitis were determined by 1 H NMR (nuclear magnetic resonance) spectroscopy. Fifty-two metabolites were quantified, and metabolic pathway analysis was performed. Multivariate analysis revealed that AIH could be differentiated from healthy controls and each of the disease controls ( p <0.001). Fifteen metabolites differentiated AIH from disease controls (PBC+chronic viral hepatitis+metabolic dysfunction-associated liver disease) (95% sensitivity and 92% specificity). Ten distinct metabolic pathways were altered in AIH compared to disease controls. The metabolic pathway of branched-chain amino acids (lower valine, leucine, and isoleucine levels and their catabolic intermediates in PBC), methionine (lower methionine, 2-aminobutyrate, and 2-hydroxybutyrate levels in PBC), alanine-aspartate-glutamate (lower metabolites in PBC), and that of metabolites associated with gut microbiota (lower choline, betaine, and dimethylamine levels in PBC) were significantly different between AIH and PBC ( p <0.01).

CONCLUSIONS

1 H NMR spectroscopy could be a promising novel tool to diagnose and study AIH pathogenesis as there is no need for much sample handling, is highly reproducible with high sensitivity and specificity, and low cost.

Isomers-oriented separation of forty-five plasma bile acids with liquid chromatography-tandem mass spectrometry

Some bile acids (BAs) were considered as biomarkers or have therapeutical effect on metabolic diseases. However, due to the existence of isomers and limitations in sensitivity, simultaneous quantification of multiple BAs remains a challenge. The aim of this study is to establish an accurate and sensitive method for the determination of multiple BAs with similar polarity. A LC-MS/MS analytical method capable of quantifying forty-five BAs simultaneously using nine stable isotope internal standards was developed and fully validated based on key isomers-oriented separation strategy. The method was further applied to analyze plasma samples to describe the dynamic profile of BAs after high glucose intake. The chromatography and mass spectrum conditions were optimized to enable the accurate quantification of forty-five BAs, while ensuring the lower limit of quantification between 0.05-10 ng/mL. The results of system suitability, linearity, dilution integrity, accuracy and precision demonstrated the good quantitative capacity and robustness of the method. A total of thirty-five BAs were quantified in plasma samples from twelve healthy Chinese individuals. The established method featured superior sensitivity and better separation efficiency compared to previous studies. Meanwhile, BAs exhibited correlations with glucose and insulin, suggesting their potential as biomarkers for metabolic disorders.

NAFLD in the 21st Century: Current Knowledge Regarding Its Pathogenesis, Diagnosis and Therapeutics

Non-alcoholic fatty liver disease (NAFLD) is a major public health issue worldwide. It is the most common liver disease in Western countries, andits global prevalence is estimated to be up to 35%. However, its diagnosis may be elusive, because liver biopsy is relatively rarely performed and usually only in advanced stages of the disease. Therefore, several non-invasive scores may be applied to more easily diagnose and monitor NAFLD. In this review, we discuss the various biomarkers and imaging scores that could be useful in diagnosing and managing NAFLD. Despite the fact that general measures, such as abstinence from alcohol and modulation of other cardiovascular disease risk factors, should be applied, the mainstay of prevention and management is weight loss. Bariatric surgery may be suggested as a means to confront NAFLD. In addition, pharmacological treatment with GLP-1 analogues or the GIP agonist tirzepatide may be advisable. In this review, we focus on the utility of GLP-1 analogues and GIP agonists in lowering body weight, their pharmaceutical potential, and their safety profile, as already evidenced inanimal and human studies. We also elaborate on other options, such as the use of vitamin E, probiotics, especially next-generation probiotics, and prebiotics in this context. Finally, we explore future perspectives regarding the administration of GLP-1 analogues, GIP agonists, and probiotics/prebiotics as a means to prevent and combat NAFLD. The newest drugs pegozafermin and resmetiron, which seem to be very promising, arealso discussed.

Non-invasive diagnosis of non-alcoholic fatty liver disease: Current status and future perspective

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease throughout the world. Hepatocellular carcinoma (HCC) and liver cirrhosis can result from nonalcoholic steatohepatitis (NASH), the severe stage of NAFLD progression. By some estimates, NAFLD affects almost one-third of the world's population, which is completely new and serious public health issue. Unfortunately, NAFLD is diagnosed by exclusion, and the gold standard for identifying NAFLD/NASH and reliably measuring liver fibrosis remains liver biopsy, which is an invasive, costly, time-consuming procedure and involves variable inter-observer diagnosis. With the progress of omics and imaging techniques, numerous non-invasive serological assays have been generated and developed. On the basis of these developments, non-invasive biomarkers and imaging techniques have been combined to increase diagnostic accuracy. This review provides information for the diagnosis and assessment of NAFLD/NASH in clinical practice going forward and may assist the clinician in making an early and accurate diagnosis and in proposing a cost-effective patient surveillance. We discuss newly identified and validated non-invasive diagnostic methods from biopsy-confirmed NAFLD patient studies and their implementation in clinical practice, encompassing NAFLD/NASH diagnosis and differentiation, fibrosis assessment, and disease progression monitoring. A series of tests, including 20-carboxy arachidonic acid (20-COOH AA) and 13,14-dihydro-15-keto prostaglandin D2 (dhk PGD2), were found to be potentially the most accurate non-invasive tests for diagnosing NAFLD. Additionally, the Three-dimensional magnetic resonance imaging (3D-MRE), combination of the FM-fibro index and Liver stiffness measurement (FM-fibro LSM index) and the machine learning algorithm (MLA) tests are more accurate than other tests in assessing liver fibrosis. However, it is essential to use bigger cohort studies to corroborate a number of non-invasive diagnostic tests with extremely elevated diagnostic values.

Association of urinary chlorpyrifos, paraquat, and cyproconazole levels with the severity of fatty liver based on MRI

BACKGROUND

The objective of this study was to detect the urinary levels of chlorpyrifos, paraquat, and cyproconazole in residents living in Fuyang City and to analyze the correlation between these urinary pesticides levels and the severity of fatty liver disease (FLD).

METHODS

All participants' fat fraction (FF) values were recorded by MRI (Magnetic resonance imaging). First-morning urine samples were collected from 53 participants from Fuyang Peoples'Hospital. The levels of three urinary pesticides were measured using β-glucuronidase hydrolysis followed by a. The results were analyzed by using Pearson correlation analysis and binary logistic regression analysis to reveal the correlation between three urinary pesticides and the severity of fatty liver.

RESULTS

53 individuals were divided into 3 groups based on the results from MRI, with 20 cases in the normal control group, 16 cases in the mild fatty liver group, and 17 cases in the moderate and severe fatty liver group. Urinary chlorpyrifos level was increased along with the increase of the severity of fatty liver. Urinary paraquat level was significantly higher both in the low-grade fatty liver group and moderate & serve grade fatty liver group compared with the control group. No significant differences in urinary cyproconazole levels were observed among the three groups. Furthermore, urinary chlorpyrifos and paraquat levels were positively correlated with FF value. And chlorpyrifos was the risk factor that may be involved in the development of FLD and Receiver Operating Characteristic curve (ROC curve) analysis showed that chlorpyrifos and paraquat may serve as potential predictors of FLD.

CONCLUSION

The present findings indicate urinary chlorpyrifos and paraquat were positively correlated with the severity of fatty liver. Moreover, urinary chlorpyrifos and paraquat have the potential to be considered as the predictors for development of FLD. Thus, this study may provide a new perspective from the environmental factors for the diagnosis, prevention, and treatment of FLD.

Causal association between 637 human metabolites and ovarian cancer: a mendelian randomization study

BACKGROUND

Current evidence suggests a significant association between metabolites and ovarian cancer (OC); however, the causal relationship between the two remains unclear. This study employs Mendelian randomization (MR) to investigate the causal effects between different metabolites and OC.

METHODS

In this study, a total of 637 metabolites were selected as the exposure variables from the Genome-wide Association Study (GWAS) database ( http://gwas.mrcieu.ac.uk/datasets/ ). The OC related GWAS dataset (ieu-b-4963) was chosen as the outcome variable. R software and the TwoSampleMR package were utilized for the analysis in this study. MR analysis employed the inverse variance-weighted method (IVW), MR-Egger and weighted median (WM) for regression fitting, taking into consideration potential biases caused by linkage disequilibrium and weak instrument variables. Metabolites that did not pass the tests for heterogeneity and horizontal pleiotropy were considered to have no significant causal effect on the outcome. Steiger's upstream test was used to determine the causal direction between the exposure and outcome variables.

RESULTS

The results from IVW analysis revealed that a total of 31 human metabolites showed a significant causal effect on OC (P < 0.05). Among them, 9 metabolites exhibited consistent and stable causal effects, which were confirmed by Steiger's upstream test (P < 0.05). Among these 9 metabolites, Androsterone sulfate, Propionylcarnitine, 5alpha-androstan-3beta,17beta-diol disulfate, Total lipids in medium VLDL and Concentration of medium VLDL particles demonstrated a significant positive causal effect on OC, indicating that these metabolites promote the occurrence of OC. On the other hand, X-12,093, Octanoylcarnitine, N2,N2-dimethylguanosine, and Cis-4-decenoyl carnitine showed a significant negative causal association with OC, suggesting that these metabolites can inhibit the occurrence of OC.

CONCLUSIONS

The study revealed the complex effect of metabolites on OC through Mendelian randomization. As promising biomarkers, these metabolites are worthy of further clinical validation.

Phenomic Imaging

Human phenomics is defined as the comprehensive collection of observable phenotypes and characteristics influenced by a complex interplay among factors at multiple scales. These factors include genes, epigenetics at the microscopic level, organs, microbiome at the mesoscopic level, and diet and environmental exposures at the macroscopic level. "Phenomic imaging" utilizes various imaging techniques to visualize and measure anatomical structures, biological functions, metabolic processes, and biochemical activities across different scales, both in vivo and ex vivo. Unlike conventional medical imaging focused on disease diagnosis, phenomic imaging captures both normal and abnormal traits, facilitating detailed correlations between macro- and micro-phenotypes. This approach plays a crucial role in deciphering phenomes. This review provides an overview of different phenomic imaging modalities and their applications in human phenomics. Additionally, it explores the associations between phenomic imaging and other omics disciplines, including genomics, transcriptomics, proteomics, immunomics, and metabolomics. By integrating phenomic imaging with other omics data, such as genomics and metabolomics, a comprehensive understanding of biological systems can be achieved. This integration paves the way for the development of new therapeutic approaches and diagnostic tools.

Isotope Labeling and Biochemical Assessment of Liver-Triacylglycerol in Patients with Different Levels of Histologically-Graded Liver Disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) prevalence is rapidly growing, and fatty liver has been found in a quarter of the US population. Increased liver lipids, particularly those derived from the pathway of de novo lipogenesis (DNL), have been identified as a hallmark feature in individuals with high liver fat. This has led to much activity in basic science and drug development in this area. No studies to date have investigated the contribution of DNL across a spectrum of disease, although it is clear that inhibition of DNL has been shown to reduce liver fat.

OBJECTIVES

The purpose of this study was to determine whether liver lipid synthesis increases across the continuum of liver injury.

METHODS

Individuals (n = 49) consumed deuterated water for 10 d before their scheduled bariatric surgeries to label DNL; blood and liver tissue samples were obtained on the day of the surgery. Liver lipid concentrations were quantitated, and levels of protein and gene expression assessed.

RESULTS

Increased liver DNL, measured isotopically, was significantly associated with liver fatty acid synthase protein content (R = 0.470, P = 0.003), total steatosis assessed by histology (R = 0.526, P = 0.0008), and the fraction of DNL fatty acids in plasma very low-density lipoprotein-triacylglycerol (R = 0.747, P < 0.001). Regression analysis revealed a parabolic relationship between fractional liver DNL (percent) and NAFLD activity score (R = 0.538, P = 0.0004).

CONCLUSION

These data demonstrate that higher DNL is associated with early to mid stages of liver disease, and this pathway may be an effective target for the treatment of NAFLD and nonalcoholic steatohepatitis. This study was registered at clinicaltrials.gov as NCT03683589.

Advances in Noninvasive Biomarkers for Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) currently represents one of the most common liver diseases worldwide. Early diagnosis and disease staging is crucial, since it is mainly asymptomatic, but can progress to nonalcoholic steatohepatitis (NASH) or cirrhosis or even lead to the development of hepatocellular carcinoma. Over time, efforts have been put into developing noninvasive diagnostic and staging methods in order to replace the use of a liver biopsy. The noninvasive methods used include imaging techniques that measure liver stiffness and biological markers, with a focus on serum biomarkers. Due to the impressive complexity of the NAFLD's pathophysiology, biomarkers are able to assay different processes involved, such as apoptosis, fibrogenesis, and inflammation, or even address the genetic background and "omics" technologies. This article reviews not only the currently validated noninvasive methods to investigate NAFLD but also the promising results regarding recently discovered biomarkers, including biomarker panels and the combination of the currently validated evaluation methods and serum markers.

From NAFLD to HCC: Advances in noninvasive diagnosis

Non-alcoholic fatty liver disease (NAFLD) has gradually become one of the major liver health problems in the world. The dynamic course of the disease goes through steatosis, inflammation, fibrosis, and carcinoma. Before progressing to carcinoma, timely and effective intervention will make the condition better, which highlights the importance of early diagnosis. With the further study of the biological mechanism in the pathogenesis and progression of NAFLD, some potential biomarkers have been discovered, and the possibility of their clinical application is gradually being discussed. At the same time, the progress of imaging technology and the emergence of new materials and methods also provide more possibilities for the diagnosis of NAFLD. This article reviews the diagnostic markers and advanced diagnostic methods of NAFLD in recent years.

Serum Metabolites Are Associated With HFpEF in Biopsy-Proven Nonalcoholic Fatty Liver Disease

Background Nonalcoholic fatty liver disease (NAFLD) and heart failure with preserved ejection fraction (HFpEF) share common risk factors, including obesity and diabetes. They are also thought to be mechanistically linked. The aim of this study was to define serum metabolites associated with HFpEF in a cohort of patients with biopsy-proven NAFLD to identify common mechanisms. Methods and Results We performed a retrospective, single-center study of 89 adult patients with biopsy-proven NAFLD who had transthoracic echocardiography performed for any indication. Metabolomic analysis was performed on serum using ultrahigh performance liquid and gas chromatography/tandem mass spectrometry. HFpEF was defined as ejection fraction >50% plus at least 1 echocardiographic feature of HFpEF (diastolic dysfunction, abnormal left atrial size) and at least 1 heart failure sign or symptom. We performed generalized linear models to evaluate associations between individual metabolites, NAFLD, and HFpEF. Thirty-seven out of 89 (41.6%) patients met criteria for HFpEF. A total of 1151 metabolites were detected; 656 were analyzed after exclusion of unnamed metabolites and those with >30% missing values. Fifty-three metabolites were associated with the presence of HFpEF with unadjusted P value <0.05; none met statistical significance after adjustment for multiple comparisons. The majority (39/53, 73.6%) were lipid metabolites, and levels were generally increased. Two cysteine metabolites (cysteine s-sulfate and s-methylcysteine) were present at significantly lower levels in patients with HFpEF. Conclusions We identified serum metabolites associated with HFpEF in patients with biopsy-proven NAFLD, with increased levels of multiple lipid metabolites. Lipid metabolism could be an important pathway linking HFpEF to NAFLD.

Potential Hepatic Lipid Markers Associated with Nonalcoholic Steatohepatitis and Fibrosis in Morbid Obesity Patients

This study investigated differences in lipidomic profile features in nonalcoholic steatohepatitis (NASH) between mild and significant liver fibrosis cases among patients with morbid obesity. Wedge liver biopsy was performed during sleeve gastrectomy and significant liver fibrosis was defined as a fibrosis score ≥ 2. We selected patients with NASH with non/mild fibrosis (stage F0-F1; n = 30) and NASH with significant fibrosis (stage F2-F4; n = 30). The results of the liver tissue lipidomic analysis revealed that the fold changes of triglyceride (TG) (52:6); cholesterol ester (CE) (20:1); phosphatidylcholine (PC) (38:0) and (50:8); phosphatidic acid (PA) (40:4); phosphatidylinositol (PI) (49:4); phosphatidylglycerol (PG) (40:2); and sphingomyelin (SM) (35:0) and (37:0) were significantly lower in patients with NASH with F2-F4 than those with NASH with F0-F1 (p < 0.05). However, the fold changes of PC (42:4) were relatively higher in patients with NASH with stage 2-4 fibrosis (p < 0.05). Moreover, predictive models incorporating serum markers levels, ultrasonographic studies, and levels of specific lipid components [PC (42:4) and PG (40:2)] yielded the highest area under receiver operating curve (0.941), suggesting a potential correlation between NASH fibrosis stages and liver lipid accumulation among specific lipid species subclasses. This study demonstrated that the concentrations of particular lipid species in the liver correlate with NASH fibrosis stages and may indicate hepatic steatosis regression or progression in patients with morbid obesity.

Accuracy of Noninvasive Diagnostic Tests for the Detection of Significant and Advanced Fibrosis Stages in Nonalcoholic Fatty Liver Disease: A Systematic Literature Review of the US Studies

BACKGROUND

The purpose of this systematic literature review (SLR) was to evaluate the accuracy of noninvasive diagnostic tools in detecting significant or advanced (F2/F3) fibrosis among patients with nonalcoholic fatty liver (NAFL) in the US healthcare context.

METHODS

The SLR was conducted in PubMed and Web of Science, with an additional hand search of public domains and citations, in line with the PRISMA statement. The study included US-based original research on diagnostic test sensitivity, specificity and accuracy.

RESULTS

Twenty studies were included in qualitative evidence synthesis. Imaging techniques with the highest diagnostic accuracy in F2/F3 detection and differentiation were magnetic resonance elastography and vibration-controlled transient elastography. The most promising standard blood biomarkers were NAFLD fibrosis score and FIB-4. The novel diagnostic tools showed good overall accuracy, particularly a score composed of body mass index, GGT, 25-OH-vitamin D, and platelet count. The novel approaches in liver fibrosis detection successfully combine imaging techniques and blood biomarkers.

CONCLUSIONS

While noninvasive techniques could overcome some limitations of liver biopsy, a tool that would provide a sufficiently sensitive and reliable estimate of changes in fibrosis development and regression is still missing.

Application of metabolomics in the diagnosis of non-alcoholic fatty liver disease and the treatment of traditional Chinese medicine

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease around the world, and it often coexists with insulin resistance-related diseases including obesity, diabetes, hyperlipidemia, and hypertension, which seriously threatens human health. Better prevention and treatment strategies are required to improve the impact of NAFLD. Although needle biopsy is an effective tool for diagnosing NAFLD, this method is invasive and difficult to perform. Therefore, it is very important to develop more efficient approaches for the early diagnosis of NAFLD. Traditional Chinese medicine (TCM) can play a certain role in improving symptoms and protecting target organs, and its mechanism of action needs to be further studied. Metabolomics, the study of all metabolites that is thought to be most closely associated with the patients’ characters, can provide useful clinically biomarkers that can be applied to NAFLD and may open up new methods for diagnosis. Metabolomics technology is consistent with the overall concept of TCM, and it can also be used as a potential mechanism to explain the effects of TCM by measuring biomarkers by metabolomics. Based on PubMed/MEDLINE and other databases, this paper retrieved relevant literature NAFLD and TCM intervention in NAFLD using metabolomics technology in the past 5 years were searched, and the specific metabolites associated with the development of NAFLD and the potential mechanism of Chinese medicine on improving symptoms were summarized.

Clinical Phenotyping and the Application of Precision Medicine in MAFLD

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Noninvasive Risk Stratification for Nonalcoholic Fatty Liver Disease Among Living Liver Donor Candidates: A Proposed Algorithm

To reduce waitlist mortality, living donor liver transplantation (LDLT) has increased over the past decade in the United States, but not at a rate sufficient to completely mitigate organ shortage. As a result, there are ongoing efforts to expand the living liver donor pool. Simultaneously, the prevalence of nonalcoholic fatty liver disease (NAFLD) in the general population has increased, which has significant implications on the pool of potential living liver donors. As such, a clinical assessment algorithm that exhaustively evaluates for NAFLD and fibrosis is critical to the safe expansion of LDLT. An ideal algorithm would employ safe and noninvasive methods, relying on liver biopsy only when necessary. While exclusion of NAFLD and fibrosis by noninvasive means is widely studied within the general population, there are no well-accepted guidelines for evaluation of living donors using these modalities. Here we review the current literature regarding noninvasive NALFD and fibrosis evaluation and propose a potential algorithm to apply these modalities for the selection of living liver donors.

Oral and Gut Microbial Dysbiosis and Non-alcoholic Fatty Liver Disease: The Central Role of Porphyromonas gingivalis

Gut microbiota play many important roles, such as the regulation of immunity and barrier function in the intestine, and are crucial for maintaining homeostasis in living organisms. The disruption in microbiota is called dysbiosis, which has been associated with various chronic inflammatory conditions, food allergies, colorectal cancer, etc. The gut microbiota is also affected by several other factors such as diet, antibiotics and other medications, or bacterial and viral infections. Moreover, there are some reports on the oral-gut-liver axis indicating that the disruption of oral microbiota affects the intestinal biota. Non-alcoholic fatty liver disease (NAFLD) is one of the systemic diseases caused due to the dysregulation of the oral-gut-liver axis. NAFLD is the most common liver disease reported in the developed countries. It includes liver damage ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), cirrhosis, and cancer. Recently, accumulating evidence supports an association between NAFLD and dysbiosis of oral and gut microbiota. Periodontopathic bacteria, especially Porphyromonas gingivalis, have been correlated with the pathogenesis and development of NAFLD based on the clinical and basic research, and immunology. P. gingivalis was detected in the liver, and lipopolysaccharide from this bacteria has been shown to be involved in the progression of NAFLD, thereby indicating a direct role of P. gingivalis in NAFLD. Moreover, P. gingivalis induces dysbiosis of gut microbiota, which promotes the progression of NAFLD, through disrupting both metabolic and immunologic pathways. Here, we review the roles of microbial dysbiosis in NAFLD. Focusing on P. gingivalis, we evaluate and summarize the most recent advances in our understanding of the relationship between oral-gut microbiome symbiosis and the pathogenesis and progression of non-alcoholic fatty liver disease, as well as discuss novel strategies targeting both P. gingivalis and microbial dysbiosis.

Lipid alterations in chronic liver disease and liver cancer

Lipids are a complex and diverse group of molecules with crucial roles in many physiological processes, as well as in the onset, progression, and maintenance of cancers. Fatty acids and cholesterol are the building blocks of lipids, orchestrating these crucial metabolic processes. In the liver, lipid alterations are prevalent as a cause and consequence of chronic hepatitis B and C virus infections, alcoholic hepatitis, and non-alcoholic fatty liver disease and steatohepatitis. Recent developments in lipidomics have also revealed that dynamic changes in triacylglycerols, phospholipids, sphingolipids, ceramides, fatty acids, and cholesterol are involved in the development and progression of primary liver cancer. Accordingly, the transcriptional landscape of lipid metabolism suggests a carcinogenic role of increasing fatty acids and sterol synthesis. However, limited mechanistic insights into the complex nature of the hepatic lipidome have so far hindered the development of effective therapies.

Biomarkers of Metabolic (Dysfunction)-associated Fatty Liver Disease: An Update

The prevalence of metabolic (dysfunction)-associated fatty liver disease (MAFLD) is rapidly increasing and affects up to two billion individuals globally, and this has also resulted in increased risks for cirrhosis, hepatocellular carcinoma, and liver transplants. In addition, it has also been linked to extrahepatic consequences, such as cardiovascular disease, diabetes, and various types of cancers. However, only a small proportion of patients with MAFLD develop these complications. Therefore, the identification of high-risk patients is paramount. Liver fibrosis is the major determinant in developing these complications. Although, liver biopsy is still considered the gold standard for the assessment of patients with MAFLD. Because of its invasive nature, among many other limitations, the search for noninvasive biomarkers for MAFLD remains an area of intensive research. In this review, we provide an update on the current and future biomarkers of MAFLD, including a discussion of the associated genetics, epigenetics, microbiota, and metabolomics. We also touch on the next wave of multiomic-based biomarkers.

Advances in fibrosis biomarkers in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) affects a quarter of the adult world population and the degree of liver fibrosis represents the best predictor of the development of liver-related outcomes. Easily applicable and well performing non-invasive fibrosis tests can overcome the limitations of liver biopsy and are of paramount importance to identify at-risk subjects in clinical practice. While tests with optimal performance and ease of use do not exist at this stage, available markers can be divided in three broad groups: simple serum tests, complex serum tests and elastographic methods. Simple scores (such as Fibrosis-4 and NAFLD Fibrosis Score) are based on readily available biochemical data and clinical features, while complex/proprietary tests (such as Fibrotest, Enhanced Liver Fibrosis and Hepascore) directly measure markers of fibrogenesis and fibrolysis, but have higher costs. Elastography techniques estimate the degree of fibrosis from liver stiffness and are based on either ultrasound or magnetic resonance (MR) imaging. MR elastography has better performance compared with sonographic techniques and is not affected by obesity and inflammation, but is highly costly and less available. In general, non-invasive tests are able to exclude the presence of fibrosis, but their positive predictive value is low to moderate and they lead to a high number of indeterminate results. In this context, a combination of different tests might increase accuracy while reducing gray-zone results. Their ability to predict future events and response to treatment is suboptimal and needs to be studied further. Finally, recent studies have tried different approaches, spanning from "omics" to the microbiome and micro-RNAs, with some promising results.

Noninvasive assessment of fibrosis among patients with nonalcoholic fatty liver disease [NAFLD]

Nonalcoholic fatty liver disease [NAFLD] is a condition affecting a vast portion of the worldwide population. The presence of underlying fibrosis is the strongest predictor of long-term outcomes and mortality, with a graduated increase in liver-related morbidity and mortality with progression from moderate fibrosis tobiomarkers targeting collagen turnover and extracellular matrix remodeling FibroTest FAST™, Velacur™, MRE]. While many of these provide a robust, stand alone value, the accuracy of these noninvasive tests markedly increase when used in combination or in sequential order with one another. There is not a uniform consensus demonstrating superiority of any specific test. Given the growing role and accuracy of these tests, they should have an expanding role in the assessment of fibrosis across this patient population and obviate the need for liver biopsy in a large portion of patients. Future clinical studies should focus on validating these novel biomarkers, as well as optimizing the sequential or algorithmic testing when combining these noninvasive tests.

Lipoxygenases in chronic liver diseases: current insights and future perspectives

Chronic liver diseases (CLDs) caused by viral infections, alcohol/drug abuse, or metabolic disorders affect millions of people globally and have increased mortality owing to the lack of approved therapies. Lipoxygenases (LOXs) are a family of multifaceted enzymes that are responsible for the oxidation of polyunsaturated fatty acids (PUFAs) and are implicated in the pathogenesis of multiple disorders including liver diseases. This review describes the three main LOX signaling pathways - 5-, 12-, and 15-LOX - and their involvement in CLDs. We also provide recent insights and future perspectives on LOX-related hepatic pathophysiology, and discuss the potential of LOXs and LOX-derived metabolites as diagnostic biomarkers and therapeutic targets in CLDs.

Steroid Sulfation in Adrenal Tumors

CONTEXT

The adrenal cortex produces specific steroid hormones including steroid sulfates such as dehydroepiandrosterone sulfate (DHEAS), the most abundant steroid hormone in the human circulation. Steroid sulfation involves a multistep enzyme machinery that may be impaired by inborn errors of steroid metabolism. Emerging data suggest a role of steroid sulfates in the pathophysiology of adrenal tumors and as potential biomarkers.

EVIDENCE ACQUISITION

Selective literature search using "steroid," "sulfat*," "adrenal," "transport," "mass spectrometry" and related terms in different combinations.

EVIDENCE SYNTHESIS

A recent study highlighted the tissue abundance of estrogen sulfates to be of prognostic impact in adrenocortical carcinoma tissue samples using matrix-assisted laser desorption ionization mass spectrometry imaging. General mechanisms of sulfate uptake, activation, and transfer to substrate steroids are reasonably well understood. Key aspects of this pathway, however, have not been investigated in detail in the adrenal; these include the regulation of substrate specificity and the secretion of sulfated steroids. Both for the adrenal and targeted peripheral tissues, steroid sulfates may have relevant biological actions beyond their cognate nuclear receptors after desulfation. Impaired steroid sulfation such as low DHEAS in Cushing adenomas is of diagnostic utility, but more comprehensive studies are lacking. In bioanalytics, the requirement of deconjugation for gas-chromatography/mass-spectrometry has precluded the study of steroid sulfates for a long time. This limitation may be overcome by liquid chromatography/tandem mass spectrometry.

CONCLUSIONS

A role of steroid sulfation in the pathophysiology of adrenal tumors has been suggested and a diagnostic utility of steroid sulfates as biomarkers is likely. Recent analytical developments may target sulfated steroids specifically.

Defining NASH from a Multi-Omics Systems Biology Perspective

Non-alcoholic steatohepatitis (NASH) is a chronic liver disease affecting up to 6.5% of the general population. There is no simple definition of NASH, and the molecular mechanism underlying disease pathogenesis remains elusive. Studies applying single omics technologies have enabled a better understanding of the molecular profiles associated with steatosis and hepatic inflammation—the commonly accepted histologic features for diagnosing NASH, as well as the discovery of novel candidate biomarkers. Multi-omics analysis holds great potential to uncover new insights into disease mechanism through integrating multiple layers of molecular information. Despite the technical and computational challenges associated with such efforts, a few pioneering studies have successfully applied multi-omics technologies to investigate NASH. Here, we review the most recent technological developments in mass spectrometry (MS)-based proteomics, metabolomics, and lipidomics. We summarize multi-omics studies and emerging omics biomarkers in NASH and highlight the biological insights gained through these integrated analyses.

Study on the Hepatoprotection of Schisandra chinensis Caulis Polysaccharides in Nonalcoholic Fatty Liver Disease in Rats Based on Metabolomics

The aim of this study was to investigate the hepatoprotection of Schisandra chinensis Caulis polysaccharides (SCPs) in the nonalcoholic fatty liver disease (NAFLD) induced by high-fat diet (HFD) in rats. A total of 30 Wistar rats were randomly divided into the control group (CON), model group (MOD), and Schisandra chinensis caulis polysaccharide (SCP) group. Except for those in the CON group, the other rats were fed with high-fat diet for 4 weeks to establish an NAFLD model. From the 5th week, rats in the SCP group were given SCP solution (100 mg kg^-1) by gavage for 6 weeks, and those in the CON and MOD groups were given an equal volume of distilled water in the same way. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) levels in serum, the malondialdehyde (MDA) level, glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) activities in the liver tissue were detected. The small molecular metabolites in the blood of rats were determined by the metabolomics method of ultra-high-performance liquid chromatography-quadrupole/electrostatic field orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap-MS/MS) combined with multivariate analysis. The enrichment analysis and pathway analysis of the different metabolites were carried out. The therapeutic mechanism of SCP in NAFLD rats was verified by western blot. The results showed that the levels of AST, ALT, TG, TC, and LDL-C in the serum of rats in the SCP group were significantly lower, and the levels of HDL-C were significantly higher than those in the MOD group. The screening and analysis of the metabolic pathways showed that SCP could alleviate the development of NAFLD by regulating the expression of UDP-glucose pyrophosphorylase (UGP2), UDP-glucose 6-dehydrogenase (UGDH), acetyl CoA carboxylase (ACC), and fatty acid synthase (FAS) in the liver of NAFLD rats. This study may provide a theoretical basis for the development and utilization of SCP.

Risk of severe illness of COVID-19 patients with NAFLD and increased NAFLD fibrosis scores

Background

There is still little knowledge about the association of liver fibrosis with the clinical outcomes of COVID‐19 patients with non‐alcoholic fatty liver disease (NAFLD). The aim of the study was to determine the association of NAFLD fibrosis score (NFS)–determined liver fibrosis with clinical outcomes of COVID‐19 patients with NAFLD.

Methods

The NAFLD was diagnosed by the Hepatic Steatosis Index (HSI) in the absence of other causes of chronic liver diseases. NFS was used to evaluate the severity of liver fibrosis.

Results

A total of 86 COVID‐19 patients with NAFLD were included. The median age was 43.5 years, and 58.1% of patients were male. Thirty‐eight (44.2%) patients had advanced liver fibrosis according to the NFS. Multivariate analysis indicated that concurrent diabetes (odds ratio [OR] 8.264, 95% confidence interval [CI] 1.202–56.830, p = 0.032) and advanced liver fibrosis (OR 11.057, 95% CI 1.193–102.439, p = 0.034) were independent risk factors of severe illness in COVID‐19 patients with NAFLD.

Conclusion

NAFLD patients with NFS‐determined advanced liver fibrosis are at higher risk of severe COVID‐19.

Adiponectin, Leptin, and IGF-1 Are Useful Diagnostic and Stratification Biomarkers of NAFLD

Background: Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease where liver biopsy remains the gold standard for diagnosis. Here we aimed to evaluate the role of circulating adiponectin, leptin, and insulin-like growth factor 1 (IGF-1) levels as non-invasive NAFLD biomarkers and assess their correlation with the metabolome.

Materials and Methods: Leptin, adiponectin, and IGF-1 serum levels were measured by ELISA in two independent cohorts of biopsy-proven obese NAFLD patients and healthy-liver controls (discovery: 38 NAFLD, 13 controls; validation: 194 NAFLD, 31 controls) and correlated with clinical data, histology, genetic parameters, and serum metabolomics.

Results: In both cohorts, leptin increased in NAFLD vs. controls (discovery: AUROC 0.88; validation: AUROC 0.83; p < 0.0001). The leptin levels were similar between obese and non-obese healthy controls, suggesting that obesity is not a confounding factor. In the discovery cohort, adiponectin was lower in non-alcoholic steatohepatitis (NASH) vs. non-alcoholic fatty liver (AUROC 0.87; p < 0.0001). For the validation cohort, significance was attained for homozygous for PNPLA3 allele c.444C (AUROC 0.63; p < 0.05). Combining adiponectin with specific serum lipids improved the assay performance (AUROC 0.80; p < 0.0001). For the validation cohort, IGF-1 was lower with advanced fibrosis (AUROC 0.67, p < 0.05), but combination with international normalized ratio (INR) and ferritin increased the assay performance (AUROC 0.81; p < 0.01).

Conclusion: Serum leptin discriminates NAFLD, and adiponectin combined with specific lipids stratifies NASH. IGF-1, INR, and ferritin distinguish advanced fibrosis.

Recent advances in NAFLD metabolomics

The clinical phenotypes of nonalcoholic fatty liver disease (NAFLD) encompass from simple steatosis to nonalcoholic steatohepatitis (NASH) with varying degrees of fibrosis or cirrhosis. Liver biopsy has been the standard to diagnose NASH. However, there has been strong need for precise and accurate noninvasive tests because of invasiveness and sampling variability of biopsy. Metabolomics has drawn attention as a promising diagnostic methodology in the field of NAFLD, particularly to unravel metabolic alterations which plays relevant roles in the progression of NASH. There have been numerous metabolomics researches to find new biomarker of NASH in the last decade, fueled by the recent advances in the metabolomics methodology. This review briefly covers recent research advances on the lipidomics, amino acids and bile acid metabolomics regarding continuing attempts to discover relevant biomarkers for NASH.

Serum Bile Acid, Vitamin E, and Serotonin Metabolites Are Associated With Future Liver-Related Events in Nonalcoholic Fatty Liver Disease

Identifying patients at higher risk for poor outcomes from nonalcoholic fatty liver disease (NAFLD) remains challenging. Metabolomics, the comprehensive measurement of small molecules in biological samples, has the potential to reveal novel noninvasive biomarkers. The aim of this study was to determine if serum metabolite profiles in patients with NAFLD associate with future liver-related events. We performed a retrospective single-center cohort study of 187 participants with biopsy-proven NAFLD. Metabolomic analysis was performed on serum using ultrahigh performance liquid chromatography/tandem mass spectrometry and gas chromatography/mass spectrometry. We identified liver-related events (variceal bleeding, ascites, spontaneous bacterial peritonitis, hepatic encephalopathy, hepatocellular carcinoma, hepatopulmonary or hepatorenal syndrome) by manual chart review between index biopsy (2007-2013) and April 1, 2018. Generalized linear models and Cox proportional hazards models were used to test the association of metabolites with liver-related events and time to first liver-related event, controlling for covariates and fibrosis stage. Over a mean ± SD follow-up of 6.9 ± 3.2 years, 11 participants experienced 22 liver-related events. Generalized linear models revealed 53 metabolites significantly associated with liver-related events (P < 0.05). In Cox proportional hazards modeling, 69 metabolites were significantly associated with time to future liver-related events (P < 0.05), seven of which met the false discovery rate threshold of 0.10: vitamin E metabolites gamma-carboxyethyl-hydroxychroman (gamma-CEHC) and gamma-CEHC glucuronide; primary bile acid metabolite taurochenodeoxycholate; serotonin metabolite 5-hydroxyindoleacetate; and lipid metabolites (i) 2-hydroxyglutarate, (ii) 3beta,17beta-diol disulfate 1, and (iii) eicosenoyl sphingomyelin. Conclusion: Metabolites of a primary bile acid, vitamin E, and serotonin were associated with future liver-related events. Our results suggest metabolite pathways may be useful for predicting which patients with NAFLD are at higher risk for hepatic decompensation.

Steroid disulfates - Sulfation double trouble

Sulfation pathways have recently come into the focus of biomedical research. For steroid hormones and related compounds, sulfation represents an additional layer of regulation as sulfated steroids are more water-soluble and tend to be biologically less active. For steroid diols, an additional sulfation is possible, carried out by the same sulfotransferases that catalyze the first sulfation step. The steroid disulfates that are formed are the focus of this review. We discuss both their biochemical production as well as their putative biological function. Steroid disulfates have also been linked to various clinical conditions in numerous untargeted metabolomics studies. New analytical techniques exploring the biosynthetic routes of steroid disulfates have led to novel insights, changing our understanding of sulfation in human biology. They promise a bright future for research into sulfation pathways, hopefully too for the diagnosis and treatment of several associated diseases.

The Role of the Transsulfuration Pathway in Non-Alcoholic Fatty Liver Disease

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing and approximately 25% of the global population may have NAFLD. NAFLD is associated with obesity and metabolic syndrome, but its pathophysiology is complex and only partly understood. The transsulfuration pathway (TSP) is a metabolic pathway regulating homocysteine and cysteine metabolism and is vital in controlling sulfur balance in the organism. Precise control of this pathway is critical for maintenance of optimal cellular function. The TSP is closely linked to other pathways such as the folate and methionine cycles, hydrogen sulfide (H₂S) and glutathione (GSH) production. Impaired activity of the TSP will cause an increase in homocysteine and a decrease in cysteine levels. Homocysteine will also be increased due to impairment of the folate and methionine cycles. The key enzymes of the TSP, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), are highly expressed in the liver and deficient CBS and CSE expression causes hepatic steatosis, inflammation, and fibrosis in animal models. A causative link between the TSP and NAFLD has not been established. However, dysfunctions in the TSP and related pathways, in terms of enzyme expression and the plasma levels of the metabolites (e.g., homocysteine, cystathionine, and cysteine), have been reported in NAFLD and liver cirrhosis in both animal models and humans. Further investigation of the TSP in relation to NAFLD may reveal mechanisms involved in the development and progression of NAFLD.

The Role of Diagnostic Biomarkers, Omics Strategies, and Single-Cell Sequencing for Nonalcoholic Fatty Liver Disease in Severely Obese Patients

Liver disease due to metabolic dysfunction constitute a worldwide growing health issue. Severe obesity is a particularly strong risk factor for non-alcoholic fatty liver disease, which affects up to 93% of these patients. Current diagnostic markers focus on the detection of advanced fibrosis as the major predictor of liver-related morbidity and mortality. The most accurate diagnostic tools use elastography to measure liver stiffness, with diagnostic accuracies similar in normal-weight and severely obese patients. The effectiveness of elastography tools are however hampered by limitations to equipment and measurement quality in patients with very large abdominal circumference and subcutaneous fat. Blood-based biomarkers are therefore attractive, but those available to date have only moderate diagnostic accuracy. Ongoing technological advances in omics technologies such as genomics, transcriptomics, and proteomics hold great promise for discovery of biomarkers and increased pathophysiological understanding of non-alcoholic liver disease and steatohepatitis. Very recent developments have allowed for single-cell sequencing and cell-type resolution of gene expression and function. In the near future, we will therefore likely see a multitude of breakthrough biomarkers, developed from a deepened understanding of the biological function of individual cell types in the healthy and injured liver.

Liver Fibrosis in Non-alcoholic Fatty Liver Disease: From Liver Biopsy to Non-invasive Biomarkers in Diagnosis and Treatment

An increasing percentage of people have or are at risk to develop non-alcoholic fatty liver disease (NAFLD) worldwide. NAFLD comprises different stadia going from isolated steatosis to non-alcoholic steatohepatitis (NASH). NASH is a chronic state of liver inflammation that leads to the transformation of hepatic stellate cells to myofibroblasts. These cells produce extra-cellular matrix that results in liver fibrosis. In a normal situation, fibrogenesis is a wound healing process that preserves tissue integrity. However, sustained and progressive fibrosis can become pathogenic. This process takes many years and is often asymptomatic. Therefore, patients usually present themselves with end-stage liver disease e.g., liver cirrhosis, decompensated liver disease or even hepatocellular carcinoma. Fibrosis has also been identified as the most important predictor of prognosis in patients with NAFLD. Currently, only a minority of patients with liver fibrosis are identified to be at risk and hence referred for treatment. This is not only because the disease is largely asymptomatic, but also due to the fact that currently liver biopsy is still the golden standard for accurate detection of liver fibrosis. However, performing a liver biopsy harbors some risks and requires resources and expertise, hence is not applicable in every clinical setting and is unsuitable for screening. Consequently, different non-invasive diagnostic tools, mainly based on analysis of blood or other specimens or based on imaging have been developed or are in development. In this review, we will first give an overview of the pathogenic mechanisms of the evolution from isolated steatosis to fibrosis. This serves as the basis for the subsequent discussion of the current and future diagnostic biomarkers and anti-fibrotic drugs.

Gut microbiota mediated molecular events and therapy in liver diseases

Gut microbiota is a community of microorganisms that reside in the gastrointestinal tract. An increasing number of studies has demonstrated that the gut-liver axis plays a critical role in liver homeostasis. Dysbiosis of gut microbiota can cause liver diseases, including nonalcoholic fatty liver disease and alcoholic liver disease. Preclinical and clinical investigations have substantiated that the metabolites and other molecules derived from gut microbiota and diet interaction function as mediators to cause liver fibrosis, cirrhosis, and final cancer. This effect has been demonstrated to be associated with dysregulation of intrahepatic immunity and liver metabolism. Targeting these findings have led to the development of novel preventive and therapeutic strategies. Here, we review the cellular and molecular mechanisms underlying gut microbiota-mediated impact on liver disease. We also summarize the advancement of gut microbiota-based therapeutic strategies in the control of liver diseases.

The role of omics in the pathophysiology, diagnosis and treatment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a multifaceted metabolic disorder, whose spectrum covers clinical, histological and pathophysiological developments ranging from simple steatosis to non-alcoholic steatohepatitis (NASH) and liver fibrosis, potentially evolving into cirrhosis, hepatocellular carcinoma and liver failure. Liver biopsy remains the gold standard for diagnosing NAFLD, while there are no specific treatments. An ever-increasing number of high-throughput Omics investigations on the molecular pathobiology of NAFLD at the cellular, tissue and system levels produce comprehensive biochemical patient snapshots. In the clinical setting, these applications are considerably enhancing our efforts towards obtaining a holistic insight on NAFLD pathophysiology. Omics are also generating non-invasive diagnostic modalities for the distinct stages of NAFLD, that remain though to be validated in multiple, large, heterogenous and independent cohorts, both cross-sectionally as well as prospectively. Finally, they aid in developing novel therapies. By tracing the flow of information from genomics to epigenomics, transcriptomics, proteomics, metabolomics, lipidomics and glycomics, the chief contributions of these techniques in understanding, diagnosing and treating NAFLD are summarized herein.

Association between serum and dietary antioxidant micronutrients and advanced liver fibrosis in non-alcoholic fatty liver disease: an observational study

BACKGROUND

Despite clinical trials with antioxidant supplementation, few studies have been conducted to evaluate the nutritional status of antioxidant vitamins and minerals, and none have reported on the status of these serum antioxidants associated with the dietary intake of antioxidants by non-alcoholic fatty liver disease (NAFLD) patients.

OBJECTIVE

To evaluate association between serum and dietetics antioxidants with liver fibrosis in patients with NAFLD.

METHODS

Across-section analysis with out with 72 patients diagnosed with NAFLD. Hepatic fibrosis was measured by FibroScan®, and liver stiffness ≥7.9 kPa was considered to indicate advanced fibrosis. Retinol, alpha-tocopherol, ascorbic acid, beta-carotene, serum zinc, and selenium were evaluated, as was the dietary intake of these micronutrients in the previous 24 h (using 24-h dietary recall). The Mann-Whitney test was used to compare the fibrosis groups and, a linear regression analysis was performed to determine associated risk factors between age, sex, BMI, hepatic fibrosis, and serum antioxidants.

RESULTS

A high proportion of inadequate serum retinol (20.8%), vitamin C (27%), and selenium (73.6%) was observed in the patients with NAFLD, in addition to a significant inadequacy of vitamin A (98.3%) and vitamin E (100%) intake. Patients with advanced liver fibrosis had reduced levels of serum retinol (P = 0.002), with liver fibrosis being the independent risk factor associated with serum retinol lower.

CONCLUSION

Hepatic fibrosis was associated with a reduction in serum retinol and was reduced in advanced fibrosis. NAFLD patients showed an important serum deficiency and insufficient dietary intake of the evaluated micronutrients.

Prospective, Same-Day, Direct Comparison of Controlled Attenuation Parameter With the M vs the XL Probe in Patients With Nonalcoholic Fatty Liver Disease, Using Magnetic Resonance Imaging-Proton Density Fat Fraction as the Standard

BACKGROUND & AIMS

Controlled attenuation parameter (CAP) measurements using M probe have been reported to be lower than those of the XL-probe in detection of hepatic steatosis. However, there has been no direct comparison of CAP with the M vs the XL probe in patients with nonalcoholic fatty liver disease (NAFLD). We compared CAP with the M vs the XL probe for quantification of hepatic fat content, using magnetic resonance imaging proton density fat fraction (MRI-PDFF) as the standard.

METHODS

We performed a prospective study of 100 adults (mean body mass index [BMI], 30.6 ± 4.7 kg/m2) with and without NAFLD, assessed by CAP with the M probe and XL probe on the same day, at a single research center, from November 2017 through November 2018. We then measured the MRI-PDFF as the reference standard. Outcomes were presence of hepatic steatosis, defined as MRI-PDFF ≥ 5%, and detection of hepatic fat content ≥ 10%, defined as MRI-PDFF ≥ 10%. We performed area under the receiver operating characteristic curve (AUROC) analyses to assess the diagnostic accuracy of CAP for each probe in detection of hepatic steatosis (MRI-PDFF ≥ 5%) and of hepatic fat content ≥ 10%.

RESULTS

Of the study participants, 68% had an MRI-PDFF of 5% or more and 48% had an MRI-PDFF of 10% or more. The mean CAP measured by the M probe (310 ± 62 db/m) was significantly lower than by the X probe (317 ± 63 db/m) (P = .007). When M probe was used in participants with BMIs <30 kg/m² and XL probe in participants with BMIs ≥30 kg/m², the CAP measured by the M probe (312 ± 51.4 db/m) remained significantly lower than that of the XL probe (345 ± 47.6 db/m) (P = .0035.), when the MRI-PDFF was above 5%. The optimal threshold of CAP for the detection of MRI-PDFF≥5%, was 294 db/m with the M probe and 307 db/m with the XL probe. The optimal threshold of CAP for the detection of MRI-PDFF ≥ 10%, was 311 db/m with the M probe and 322 db/m with the XL probe. For only the XL probe, CAP measurements with an interquartile range below 30 dB/m detected an MRI-PDFF≥5% with a lower AUROC (0.97; 95% CI, 0.80-1.00) than CAP measurements with an interquartile range above 30 dB/m (AUROC, 0.82; 95% CI, 0.71-0.90) (P = .0129).

CONCLUSIONS

In an analysis of the same patients using CAP with the M probe and XL probe, with MRI-PDFF as the standard, we found that the M probe under-quantifies CAP values compared with the XL probe, independent of BMI. The type of probe should be considered when interpreting CAP data from patients with NAFLD.

Plasma eicosanoids as noninvasive biomarkers of liver fibrosis in patients with nonalcoholic steatohepatitis

BACKGROUND

Eicosanoid and related docosanoid polyunsaturated fatty acids (PUFAs) and their oxygenated derivatives have been proposed as noninvasive lipidomic biomarkers of nonalcoholic steatohepatitis (NASH). Therefore, we investigated associations between plasma eicosanoids and liver fibrosis to evaluate their utility in diagnosing and monitoring NASH-related fibrosis.

METHODS

Our analysis used baseline eicosanoid data from 427 patients with biopsy-confirmed nonalcoholic fatty liver disease (NAFLD), and longitudinal measurements along with liver fibrosis staging from 63 patients with NASH and stage 2/3 fibrosis followed for 24 weeks in a phase II trial.

RESULTS

At baseline, four eicosanoids were significantly associated with liver fibrosis stage: 11,12-DIHETE, tetranor 12-HETE, adrenic acid, and 14, 15-DIHETE. Over 24 weeks of follow up, a combination of changes in seven eicosanoids [5-HETE, 7,17-DHDPA, adrenic acid, arachidonic acid (AA), eicosapentaenoic acid (EPA), 16-HDOHE, and 9-HODE) had good diagnostic accuracy for the prediction of ⩾1 stage improvement in fibrosis (AUROC: 0.74; 95% CI: 0.62-0.87), and a combination of four eicosanoids (7,17-DHDPA, 14,15-DIHETRE, 9-HOTRE, and free adrenic acid) accurately predicted improvement in hepatic collagen content (AUROC: 0.72; 95% CI: 0.50-0.77).

CONCLUSION

This study provides preliminary evidence that plasma eicosanoids may serve as noninvasive biomarkers of liver fibrosis and may predict liver fibrosis improvement in NASH.