Evaluation of ballooned hepatocytes as a risk factor for future progression of fibrosis in patients with non-alcoholic fatty liver disease

Coincidental items in the definition of metabolic dysfunction-associated fatty liver are useful in identifying patients having significant fibrosis with fatty liver

AIM

We aimed to establish a method that will identify patients at a high risk for progressive phenotype of fatty liver.

METHODS

Patients with fatty liver who underwent liver biopsy between July 2008 and November 2019 were included as cohort 1, and those who underwent abdominal ultrasound screening examination by general physicians between August 2020 and May 2022 served as cohort 2. According to the definition of metabolic dysfunction-associated fatty liver (MAFLD), the subjects were classified by body mass index of ≥23, diabetes mellitus, and coexistence of two or more metabolic risk items. The progressive phenotype of MAFLD is defined by significant fibrosis complicated with either nonalcoholic fatty liver disease activity score ≥4 (BpMAFLD) or steatosis grade ≥2 by ultrasound examination (UpMAFLD).

RESULTS

One hundred sixty-eight patients and 233 patients were enrolled in cohorts 1 and 2, respectively. In cohort 1, the prevalence of BpMAFLD was 0% in patients without a complicating factor (n = 10), 13% in those with one complicating factor (n = 67), 32% in those with two (n = 73), and 44% in those with all three complicating factors (n = 36). A logistic regression analysis revealed that factors in the MAFLD definition were significantly associated with BpMAFLD. In cohort 2, a criterion of two or more positive MAFLD definitions was found to have a 97.4% negative predictive value for the diagnosis of UpMAFLD.

CONCLUSION

Patients with two or more complicating factors in the MAFLD definition should have further evaluation for liver fibrosis.

Hepatic Stellate Cells: Dictating Outcome in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a fast growing, chronic liver disease affecting ∼25% of the global population. Nonalcoholic fatty liver disease severity ranges from the less severe simple hepatic steatosis to the more advanced nonalcoholic steatohepatitis (NASH). The presence of NASH predisposes individuals to liver fibrosis, which can further progress to cirrhosis and hepatocellular carcinoma. This makes hepatic fibrosis an important indicator of clinical outcomes in patients with NASH. Hepatic stellate cell activation dictates fibrosis development during NASH. Here, we discuss recent advances in the analysis of the profibrogenic pathways and mediators of hepatic stellate cell activation and inactivation, which ultimately determine the course of disease in nonalcoholic fatty liver disease/NASH.

Influence of landscape ecology and physiological implications in bats from different trophic guilds

Bats may serve as bioindicators of human impact on landscape ecology. This study aimed to evaluate the health condition of bats from different food guilds captured in two areas with different land use profiles in Brazil and to compare data on the oxidant-antioxidant balance and histopathological changes due to different anthropogenic pressures. Bats were collected from a protected area in Serra do Cipó National Park (SCNP), MG, Brazil, and an area with intense agricultural activity in the municipality of Uberaba (UB), MG, Brazil. Despite the differences in land use and occupation between the studied areas, bats showed similar responses. However, the trophic guilds were affected differently. Frugivorous bats in both areas showed lower activities of the enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) and concentrations of malondialdehyde (MDA) than other guilds, which can be explained by the greater intake of antioxidants from the diet in addition to the lower production of reactive oxygen species (ROS). Histopathological analysis of the livers revealed that the animals had a similar prevalence in the two areas, with some differences related to guilds. Compared with other bats, hematophagous bats from SCNP had a higher prevalence of steatosis and, together with frugivorous bats from Uberaba, had higher frequencies of ballooning degeneration, suggesting that these animals are subjected to anthropogenic factors capable of inducing disturbances in hepatic metabolism. Hematophagous bats from Uberaba had a higher prevalence of portal inflammation, while insectivorous bats from Uberaba had a higher prevalence of lobular and portal inflammation. The profiles of use and occupation of the areas are different; Uberaba bats seem to face worse conditions because they show more liver damage owing to lipoperoxidation.

Fibrogenic Pathways in Metabolic Dysfunction Associated Fatty Liver Disease (MAFLD)

The prevalence of nonalcoholic fatty liver disease (NAFLD), recently also re-defined as metabolic dysfunction associated fatty liver disease (MAFLD), is rapidly increasing, affecting ~25% of the world population. MALFD/NAFLD represents a spectrum of liver pathologies including the more benign hepatic steatosis and the more advanced non-alcoholic steatohepatitis (NASH). NASH is associated with enhanced risk for liver fibrosis and progression to cirrhosis and hepatocellular carcinoma. Hepatic stellate cells (HSC) activation underlies NASH-related fibrosis. Here, we discuss the profibrogenic pathways, which lead to HSC activation and fibrogenesis, with a particular focus on the intercellular hepatocyte–HSC and macrophage–HSC crosstalk.

In vitro ballooned hepatocytes can be produced by primary human hepatocytes and hepatic stellate cell sheets

Despite the increasing prevalence of Nonalcoholic steatohepatitis (NASH) worldwide, there is no effective treatment available for this disease. “Ballooned hepatocyte” is a characteristic finding in NASH and is correlated with disease prognosis, but their mechanisms of action are poorly understood; furthermore, neither animal nor in vitro models of NASH have been able to adequately represent ballooned hepatocytes. Herein, we engineered cell sheets to develop a new in vitro model of ballooned hepatocytes. Primary human hepatocytes (PHH) and Hepatic stellate cells (HSC) were co-cultured to produce cell sheets, which were cultured in glucose and lipid containing medium, following which histological and functional analyses were performed. Histological findings showed hepatocyte ballooning, accumulation of fat droplets, abnormal cytokeratin arrangement, and the presence of Mallory–Denk bodies and abnormal organelles. These findings are similar to those of ballooned hepatocytes in human NASH. Functional analysis showed elevated levels of TGFβ-1, SHH, and p62, but not TNF-α, IL-8. Exposure of PHH/HSC sheets to a glucolipotoxicity environment induces ballooned hepatocyte without inflammation. Moreover, fibrosis is an important mechanism underlying ballooned hepatocytes and could be the basis for the development of a new in vitro NASH model with ballooned hepatocytes.

In vitro models for non-alcoholic fatty liver disease: Emerging platforms and their applications

Non-alcoholic fatty liver disease (NAFLD) represents a global healthcare challenge, affecting 1 in 4 adults, and death rates are predicted to rise inexorably. The progressive form of NAFLD, non-alcoholic steatohepatitis (NASH), can lead to fibrosis, cirrhosis, and hepatocellular carcinoma. However, no medical treatments are licensed for NAFLD-NASH. Identifying efficacious therapies has been hindered by the complexity of disease pathogenesis, a paucity of predictive preclinical models and inadequate validation of pharmacological targets in humans. The development of clinically relevant in vitro models of the disease will pave the way to overcome these challenges. Currently, the combined application of emerging technologies (e.g., organ-on-a-chip/microphysiological systems) and control engineering approaches promises to unravel NAFLD biology and deliver tractable treatment candidates. In this review, we will describe advances in preclinical models for NAFLD-NASH, the recent introduction of novel technologies in this space, and their importance for drug discovery endeavors in the future.

In vitro models for non-alcoholic fatty liver disease: Emerging platforms and their applications

Non-alcoholic fatty liver disease (NAFLD) represents a global healthcare challenge, affecting 1 in 4 adults, and death rates are predicted to rise inexorably. The progressive form of NAFLD, non-alcoholic steatohepatitis (NASH), can lead to fibrosis, cirrhosis, and hepatocellular carcinoma. However, no medical treatments are licensed for NAFLD-NASH. Identifying efficacious therapies has been hindered by the complexity of disease pathogenesis, a paucity of predictive preclinical models and inadequate validation of pharmacological targets in humans. The development of clinically relevant in vitro models of the disease will pave the way to overcome these challenges. Currently, the combined application of emerging technologies (e.g., organ-on-a-chip/microphysiological systems) and control engineering approaches promises to unravel NAFLD biology and deliver tractable treatment candidates. In this review, we will describe advances in preclinical models for NAFLD-NASH, the recent introduction of novel technologies in this space, and their importance for drug discovery endeavors in the future.

Predictive value of cytokeratin-18 fragment levels for diagnosing steatohepatitis in patients with nonalcoholic fatty liver disease

OBJECTIVE

Several noninvasive markers have been developed to predict nonalcoholic steatohepatitis (NASH). We investigated the predictive value of the cytokeratin-18 fragment (CK18-F) level and FIB-4 index for diagnosing NASH in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

A total of 246 patients histologically diagnosed with NASH (n = 185) or nonalcoholic fatty liver (n = 61) were enrolled. We analyzed weighted receiver operating characteristic (ROC) curves for the prediction of NASH and determined the relationship between the CK18-F level and the histological features of NASH. In addition, we investigated the predictive value of the combination of the CK18-F level and FIB-4 index for diagnosing NASH.

RESULTS

The area under the ROC curve (AUROC) value of the CK18-F level was 0.77. With a CK18-F cutoff level of 260 U/L, the sensitivity and specificity for diagnosing NASH were 82.7 and 57.4%, respectively. Multiple comparisons showed that the CK18-F level did not differ among fibrosis stages but did significantly differ among hepatocyte ballooning grades. Overall, 95.7% (66/69) of patients with a FIB-4 index of ≥2.67 had NASH. In patients with a FIB-4 index of <2.67, the AUROC value of the CK18-F level for predicting NASH was 0.77 and a CK18-F cutoff level of 260 U/L resulted in a sensitivity and specificity of 82.4 and 56.9%.

CONCLUSIONS

The CK18-F level had a good predictive ability for diagnosing NASH in patients with NAFLD. Additionally, the combination of the CK18-F level and FIB-4 index accurately and noninvasively predicted NASH, even those with a low FIB-4 index.

Glycemic Control Predicts Severity of Hepatocyte Ballooning and Hepatic Fibrosis in Nonalcoholic Fatty Liver Disease

BACKGROUND AND AIMS

Whether glycemic control, as opposed to diabetes status, is associated with the severity of NAFLD is open for study. We aimed to evaluate whether degree of glycemic control in the years preceding liver biopsy predicts the histological severity of NASH.

APPROACH AND RESULTS

Using the Duke NAFLD Clinical Database, we examined patients with biopsy-proven NAFLD/NASH (n = 713) and the association of liver injury with glycemic control as measured by hemoglobin A1c (HbA1c). The study cohort was predominantly female (59%) and White (84%) with median (interquartile range) age of 50 (42, 58) years; 49% had diabetes (n = 348). Generalized linear regression models adjusted for age, sex, race, diabetes, body mass index, and hyperlipidemia were used to assess the association between mean HbA1c over the year preceding liver biopsy and severity of histological features of NAFLD/NASH. Histological features were graded and staged according to the NASH Clinical Research Network system. Group-based trajectory analysis was used to examine patients with at least three HbA1c (n = 298) measures over 5 years preceding clinically indicated liver biopsy. Higher mean HbA1c was associated with higher grade of steatosis and ballooned hepatocytes, but not lobular inflammation. Every 1% increase in mean HbA1c was associated with 15% higher odds of increased fibrosis stage (OR, 1.15; 95% CI, 1.01, 1.31). As compared with good glycemic control, moderate control was significantly associated with increased severity of ballooned hepatocytes (OR, 1.74; 95% CI, 1.01, 3.01; P = 0.048) and hepatic fibrosis (HF; OR, 4.59; 95% CI, 2.33, 9.06; P < 0.01).

CONCLUSIONS

Glycemic control predicts severity of ballooned hepatocytes and HF in NAFLD/NASH, and thus optimizing glycemic control may be a means of modifying risk of NASH-related fibrosis progression.

High frequency and long persistency of ballooning hepatocyte were associated with glucose intolerance in patients with severe obesity

Nonalcoholic steatohepatitis (NASH) and glucose intolerance are associated with an increased risk of mortality in patients with severe obesity; however, whether histological findings of the liver are related to glucose intolerance in these patients remain unknown. Sixty-nine consecutive patients who underwent metabolic surgery between June 2008 and February 2020 were included; histological findings of the liver and laboratory data were analyzed. Twenty patients with biopsy-proven NASH were chronologically evaluated using sequential biopsies; data before metabolic surgery was considered as the baseline. Glucose intolerance—demonstrated by an increased area under the curve (AUC) for blood sugar (BS) during the 75-g oral glucose tolerance test—and increased homeostatic model assessment for insulin resistance (HOMA-IR) correlated with the grade of hepatocyte ballooning in patients. Patients with persistent ballooning at the follow-up biopsy had a higher HOMA-IR, high AUC for BS, and lower adiponectin level than those in patients in whom ballooning was eliminated, while there was no significant difference in body weight. We concluded that glucose intolerance was associated with the grade of hepatocyte ballooning; additionally, persistent hepatocyte ballooning sustained glucose intolerance, while elimination of hepatocyte ballooning improved the condition. Glucose intolerance may, thus, mediate balloon formation of the hepatocyte.

Non-invasive biomarkers in predicting non-alcoholic steatohepatitis and assessing liver fibrosis: systematic review and meta-analysis

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is characterized by hepatic steatosis with inflammation, ballooned hepatocytes, and possible fibrosis, which may progress to liver cirrhosis. Although liver biopsy, remains the diagnostic gold standard of NASH, several noninvasive biomarkers have been studied, to avoid the need for this invasive procedure. We performed a systematic review with meta-analysis to evaluate the accuracy of several noninvasive biomarkers in predicting NASH and assessing liver fibrosis in NASH patients.

EVIDENCE ACQUISITION

An electronic search on PubMed and EMBASE was systematically performed. The principal summary outcome was the area under the curve (AUC), assessing the accuracy of NashTest, BARD (body mass index, AST/ALT ratio, diabetes) score, NAFLD fibrosis score (NFS), APRI (aspartate aminotransferase-to-platelet ratio index), and fibrosis-4 (FIB-4) index in predicting NASH and assessing liver fibrosis.

EVIDENCE SYNTHESIS

Thirteen studies involving 6,557 adult patients were included in the qualitative assessment of this review, out of which, six studies were included in the quantitative assessment. Prediction of NASH was evaluated better using NFS (AUC of 0.687) and FIB-4 (AUC of 0.729). Fibrosis stages 0 vs. 1-4 was diagnosed better using NFS (AUC of 0.718) and FIB-4 (AUC of 0.723). Advanced fibrosis was assessed better by BARD (AUC of 0.673), APRI (AUC of 0.762), NFS (AUC of 0.787) and FIB-4 (AUC of 0.821).

CONCLUSIONS

FIB-4 predicted NASH and quantified liver fibrosis, stages 0 vs. 1-4 more precisely compared to NFS, APRI, and BARD. However, considering that methodological quality of the assessed studies is limited, the results should be considered with caution.

Fatty acid-driven modifications in T-cell profiles in non-alcoholic fatty liver disease patients

BACKGROUND

The interaction between T-cells/fatty acids involved in non-alcoholic fatty liver disease (NAFLD) and liver fibrosis progression is poorly understood. In this study, we conducted a comprehensive analysis of T-cell profiles of NAFLD patients to better understand their relationship with fatty acids and relevance to liver fibrosis.

METHODS

We analyzed the differences in T-cell profiles of peripheral blood mononuclear cells (PBMCs) between 40 NAFLD patients and 5 healthy volunteers (HVs), and their relationship with liver fibrosis stage or progression. Moreover, we analyzed the relationship between T-cell profiles and fatty acid compositions in vivo, and changes in T-cell profiles after treatment with fatty acids in vitro.

RESULTS

T-cell profiles of NAFLD patients were different from those of HVs. The CD25⁺CD45⁺CD4⁺ T-cell frequency was increased in NAFLD patients with high liver fibrosis stage and progression, and this indicated immune activation. Despite such a state of immune activation, the PD1⁺CD4⁺ T-cell frequency was decreased in the same patients group. The PD1⁺CD4⁺ T-cell frequency had a significantly negative correlation with the serum fatty acid composition ratio C16:1n7/C16:0. Moreover, the PD1⁺CD4⁺ T-cell frequency was significantly decreased by in vitro treatment with fatty acids. In addition, its rate of frequency change was significantly different between C16:0 and C16:1n7 and decreased by artificially increasing the C16:1n7/C16:0 ratio.

CONCLUSIONS

The analysis of PBMCs in NAFLD patients showed that T-cell profiles were different from those of HVs. And, it suggested that fatty acids modified T-cell profiles and were involved in liver fibrosis in NAFLD patients.

Non-invasive diagnosis of non-alcoholic steatohepatitis and advanced fibrosis in Japan: A targeted literature review

Despite the invasive nature of liver biopsy, it remains the current standard for diagnosing non-alcoholic steatohepatitis (NASH) and fibrosis staging. Given the rising prevalence of non-alcoholic fatty liver disease (NAFLD) in Japan, there is a need for reliable non-invasive tests to accurately and efficiently identify NASH and advanced (F3/F4) fibrosis. A review of published works from English and Japanese sources was undertaken in PubMed, Embase, and Ichushi Web to identify studies reporting diagnostic characteristics of NITs in biopsy-proven Japanese NAFLD/NASH patients including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve. The performance of non-invasive tests for two diagnostic questions were assessed, namely: (i) identifying NASH cases among NAFLD; and (ii) distinguishing advanced fibrosis (F3-4) from milder fibrosis (F0-2). Twenty-five studies reported outcomes for serum biomarkers, imaging, scoring systems, and novel complex techniques (based on multivariable regression models) for both diagnostic questions. Serum biomarkers were the most commonly assessed method for NASH identification, whereas scoring systems and imaging techniques were most commonly studied for fibrosis staging. In general, tests for NASH identification showed higher PPVs than NPVs, suggesting their usefulness in identifying probable NASH cases. The reverse was observed for fibrosis staging, with higher NPVs than PPVs, suggesting their use in excluding patients at low risk of F3/F4 disease rather than identifying definite F3/F4 fibrosis. In Japanese studies, simple scoring systems and imaging techniques showed particular usefulness in prediction of fibrosis staging, and combinations of serum biomarkers showed diagnostic potential for NASH screening.

Mechanisms of Fibrosis Development in Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease is the most prevalent liver disease worldwide, affecting 20%-25% of the adult population. In 25% of patients, nonalcoholic fatty liver disease progresses to nonalcoholic steatohepatitis (NASH), which increases the risk for the development of cirrhosis, liver failure, and hepatocellular carcinoma. In patients with NASH, liver fibrosis is the main determinant of mortality. Here, we review how interactions between different liver cells culminate in fibrosis development in NASH, focusing on triggers and consequences of hepatocyte-macrophage-hepatic stellate cell (HSC) crosstalk. We discuss pathways through which stressed and dead hepatocytes instigate the profibrogenic crosstalk with HSC and macrophages, including the reactivation of developmental pathways such as TAZ, Notch, and hedgehog; how clearance of dead cells in NASH via efferocytosis may affect inflammation and fibrogenesis; and insights into HSC and macrophage heterogeneity revealed by single-cell RNA sequencing. Finally, we summarize options to therapeutically interrupt this profibrogenic hepatocyte-macrophage-HSC network in NASH.

Dyslipidemia as a risk factor for liver fibrosis progression in a multicentric population with non-alcoholic steatohepatitis

Background: Nonalcoholic fatty liver disease (NAFLD) is a serious worldwide health problem, with an estimated global prevalence of 24%; it has a notable relationship with other metabolic disorders, like obesity and type 2 diabetes mellitus (T2DM). Nonalcoholic steatohepatitis (NASH) is one of the most important clinical entities of NAFLD, which is associated with an increased risk of progression to liver cirrhosis and hepatocellular carcinoma (HCC). Mexico is one of the countries with the highest prevalence of metabolic diseases; therefore, we sought to investigate the impact that these clinical entities have in the progression to advanced fibrosis in Mexican patients with NASH. Methods: We performed a multicenter retrospective cross-sectional study, from January 2012 to December 2017. A total of 215 patients with biopsy-proven NASH and fibrosis were enrolled. NASH was diagnosed according NAS score and liver fibrosis was staged by the Kleiner scoring system. For comparing the risk of liver fibrosis progression, we divided our sample into two groups. Those patients with stage F0-F2 liver fibrosis were included in the group with non-significant liver fibrosis (n=178) and those individuals with F3-F4 fibrosis were included in the significant fibrosis group (n=37). We carried out a multivariate analysis to find risk factors associated with liver fibrosis progression. Results: From the 215 patients included, 37 had significant liver fibrosis (F3-4). After logistic regression analysis T2DM (p=0.044), systemic arterial hypertension (p=0.014), cholesterol (p=0.041) and triglycerides (p=0.015) were the main predictor of advanced liver fibrosis. Conclusions: In a Mexican population, dyslipidemia was the most important risk factor associated with advanced liver fibrosis and cirrhosis.

Fatty Liver Disease: A Practical Approach

CONTEXT.—

Fatty liver disease is now one of the most commonly encountered entities in the practice of liver pathology. Distinguishing simple steatosis from steatohepatitis is critical because the latter requires follow-up because of long-term risks that include cirrhosis and hepatocellular carcinoma. An organized approach for evaluating liver biopsies with steatosis is recommended to capture all of the relevant features: (1) degree of steatosis, (2) presence or absence of ballooning degeneration, (3) lobular inflammation, and (4) fibrosis. Herein, we provide a stepwise approach that readers can use to evaluate liver biopsies with steatosis, including examples, pitfalls, differential diagnostic considerations, and suggested diagnostic phrasing.

OBJECTIVE.—

To provide a stepwise approach for the evaluation of liver biopsies showing significant steatosis (involving ≥5% of liver parenchyma).

DATA SOURCES.—

Biopsies demonstrating fatty liver disease encountered in our daily practice were examined as well as recent literature.

CONCLUSIONS.—

Effective evaluation of liver biopsies with steatosis requires careful histologic examination and correlation with clinical history, particularly regarding medications, nutrition status, and alcohol use. Examples of uniform reporting, including appropriate use of the nonalcoholic steatohepatitis Clinical Research Network Activity Score, are provided.