Hepatocellular carcinoma and other complications of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis in Japan: A structured review of published works

Recent Trends in Liver Cancer: Epidemiology, Risk Factors, and Diagnostic Techniques

Liver cancer, particularly hepatocellular carcinoma (HCC), poses a significant global health challenge due to its high mortality rate. Hepatocellular carcinoma and intrahepatic cholangiocarcinoma (ICC) are the two main types of primary liver cancer (PLC), each with its own set of complexities. Secondary or metastatic liver cancer is more common than PLC. It is frequently observed in malignancies such as colorectal, pancreatic, melanoma, lung, and breast cancer. Liver cancer is often diagnosed at an advanced stage, making it difficult to treat. This highlights the need for focused research on early detection and effective treatment strategies. This review explores the epidemiology, risk factors, and diagnostic techniques for HCC. The development of HCC involves various risk factors, including chronic liver diseases, hepatitis B and C infections, alcohol consumption, obesity, smoking, and genetic predispositions. Various invasive and non-invasive diagnostic techniques, such as biopsy, liquid biopsy, and imaging modalities like ultrasonography, computed tomography scans (CT scans), magnetic resonance imaging (MRI), and positron emission tomography (PET) scans, are utilized for HCC detection and monitoring. Advances in imaging technology and biomarker research have led to more accurate and sensitive methods for early HCC detection. We also reviewed advanced research on emerging techniques, including next-generation sequencing, metabolomics, epigenetic biomarkers, and microbiome analysis, which show great potential for advancing early diagnosis and personalized treatment strategies. This literature review provides insights into the current state of liver cancer diagnosis and promising future advancements. Ongoing research and innovation in these areas are essential for improving early diagnosis and reducing the global burden of liver cancer.

Concordance between metabolic dysfunction-associated steatotic liver disease and nonalcoholic fatty liver disease

AIM

A multisociety consensus group proposed a new nomenclature for metabolic dysfunction-associated steatotic liver disease (MASLD). Although patients with nonalcoholic fatty liver disease (NAFLD) are expected to be reclassified as patients with MASLD under the new nomenclature, the concordance between MASLD and NAFLD remains unclear. Moreover, waist circumference could be adjusted by ethnicity for diagnosing MASLD; however, there are limited data on the optimal waist circumference in the Japanese population.

METHODS

This cross-sectional study was conducted on 3709 Japanese patients with NAFLD. The primary endpoint was the prevalence of MASLD in patients with NAFLD. The difference between the original waist circumference criteria (>94 cm for men and >80 cm for women) and the Japanese metabolic syndrome criteria (≥85 cm for men and ≥90 cm for women) for concordance between NAFLD and MASLD was also investigated.

RESULTS

According to the original criteria, the prevalence of MASLD in patients with NAFLD was 96.7%. Similarly, according to the Japanese waist circumference criteria, 96.2% of patients with NAFLD could be reclassified as those with MASLD. The concordance rate was significantly higher in the original criteria than in the Japanese criteria (p = 0.02).

CONCLUSIONS

NAFLD could be considered MASLD using the original MASLD criteria in the Japanese population, and insights from NAFLD research could be applied to MASLD.

Associations of non-alcoholic fatty liver disease and cirrhosis with liver cancer in European and East Asian populations: A Mendelian randomization study

BACKGROUND

The positive relationships of non-alcoholic fatty liver disease (NAFLD) and cirrhosis with liver cancer were shown in previous observational studies, while further Mendelian randomization (MR) investigations are needed to confirm the possible causal associations.

AIMS

This study aimed to explore whether NAFLD and cirrhosis were causally related to liver cancer using MR in European and East Asian populations.

METHODS AND RESULTS

For European populations, NAFLD data were obtained from a genome-wide meta-analysis (8434 patients and 770 180 controls). The data on chronic elevation of alanine aminotransferase (cALT), a proxy of NAFLD, were derived from Million Veteran Program (68 725 patients and 95 472 controls). Cirrhosis data were collected from two sources: a genome-wide association study of five cohorts (4829 patients and 72 705 controls) and FinnGen (1931 patients and 216 861 controls). Liver cancer data were collected from FinnGen (304 patients and 174 006 controls). For East Asian populations, the data on cirrhosis (2184 patients and 210 269 controls) and hepatocellular carcinoma (1866 patients and 195 745 controls) were obtained from Biobank Japan. Three, 41, seven, six, and three single-nucleotide polymorphisms were used for NAFLD (European), cALT (European), cirrhosis (European-five cohorts), cirrhosis (European-FinnGen), and cirrhosis (East Asian), respectively. We used inverse-variance weighted as the primary method to calculate the odds ratio (OR) and 95% confidence interval (CI). Among European populations, genetically-predicted NAFLD, cALT, cirrhosis (five cohorts), and cirrhosis (FinnGen) were positively associated with liver cancer, with ORs (95% CIs) of 6.62 (3.81-11.50) (p < .001), 2.59 (1.70-3.94) (p < .001), 3.38 (2.41-4.75) (p < .001), and 2.62 (1.20-5.72) (p = .015). Among East Asian populations, there was also a positive association between genetically-predicted cirrhosis and hepatocellular carcinoma (OR = 2.12; 95% CI = 1.78-2.52; p < .001).

CONCLUSION

This study utilized MR to complementarily confirm the positive connections of NAFLD and cirrhosis with liver cancer, as identified in earlier observational research. Subsequent MR investigations involving more liver cancer cases are needed.

Benefits in routinely measured liver function tests following bariatric surgery: a retrospective cohort study

Background

Bariatric surgery is well-established to support long-term metabolic health benefits associated with considerable weight loss. Here, we aim to determine the longer-term impact of bariatric surgery on liver enzymes and associations with other metabolic improvements.

Methods

One hundred patients who underwent bariatric surgery between 2007 and 2014 were included, and changes in liver enzymes, anthropometric measures and other parameters were observed over a mean 9.8 years.

Results

At the time of surgery, the mean age was 45.4 ± 9.6 years, weight 141.2 ± 31.6 kg, and body mass index (BMI) 50.2 ± 10.1 kg/m2. Most patients underwent sleeve gastrectomy [n = 71] with a mean follow-up duration 9.8 ± 2.3 years. From baseline, alanine transaminase (ALT) reduced by 41.3% within 12 months post-operatively (36.6 ± 29.2 U/L to 21.5 ± 14.9 U/L, p < 0.001), which was sustained at recent follow-up (20.2 ± 10.7 U/L, p < 0.001). There were associated reductions in body weight, BMI, HbA1c, blood pressure and triglycerides. Patients with greater baseline ALT had the greatest reduction in ALT over follow-up.

Conclusions

Bariatric surgery is associated with rapid and sustained improvements in routine liver enzymes at 10 years, and sustained improvements in features of the metabolic syndrome.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01311-4.

Palmitoyltransferase ZDHHC3 Aggravates Nonalcoholic Steatohepatitis by Targeting S-Palmitoylated IRHOM2

Underestimation of the complexity of pathogenesis in nonalcoholic steatohepatitis (NASH) significantly encumbers development of new drugs and targeted therapy strategies. Inactive rhomboid protein 2 (IRHOM2) has a multifunctional role in regulating inflammation, cell survival, and immunoreaction. Although cytokines and chemokines promote IRHOM2 trafficking or cooperate with partner factors by phosphorylation or ubiquitin ligases-mediated ubiquitination to perform physiological process, it remains unknown whether other regulators induce IRHOM2 activation via different mechanisms in NASH progression. Here the authors find that IRHOM2 is post-translationally S-palmitoylated at C476 in iRhom homology domain (IRHD), which facilitates its cytomembrane translocation and stabilization. Fatty-acids challenge can directly promote IRHOM2 trafficking by increasing its palmitoylation. Additionally, the authors identify Zinc finger DHHC-type palmitoyltransferase 3 (ZDHHC3) as a key acetyltransferase required for the IRHOM2 palmitoylation. Fatty-acids administration enhances IRHOM2 palmitoylation by increasing the direct association between ZDHHC3 and IRHOM2, which is catalyzed by the DHHC (C157) domain of ZDHHC3. Meanwhile, a metabolic stresses-triggered increase of ZDHHC3 maintains palmitoylated IRHOM2 accumulation by blocking its ubiquitination, consequently suppressing its ubiquitin-proteasome-related degradation mediated by tripartite motif containing 31 (TRIM31). High-levels of ZDHHC3 protein abundance positively correlate with the severity of NASH phenotype in patient samples. Hepatocyte-specific dysfunction of ZDHHC3 significantly inhibits palmitoylated IRHOM2 deposition, therefore suppressing the fatty-acids-mediated hepatosteatosis and inflammation in vitro, as well as NASH pathological phenotype induced by two different high-energy diets (HFHC & WTDF) in the in vivo rodent and rabbit model. Inversely, specific restoration of ZDHHC3 in hepatocytes markedly provides acceleration over the course of NASH development via increasing palmitoylation of IRHOM2 along with suppression of ubiquitin degradation. The current work uncovers that ZDHHC3-induced palmitoylation is a novel regulatory mechanism and signal that regulates IRHOM2 trafficking, which confers evidence associating the regulation of palmitoylation with NASH progression.

Outcomes of fatty liver disease with and without metabolic comorbidities and risk factors for mortality

Background and Aim

As the clinical course of metabolic-associated fatty liver disease (MAFLD) is unclear, we compared the clinical courses of MAFLD and non-alcoholic FLD (NAFLD).

Methods

Asian FLD patients (n = 987) from 1991 to 2021 (biopsy-proven in 939) were enrolled. The patients were divided into NAFLD (N-alone, n = 92), both MAFLD and N (M&N, n = 785), and M-alone (n = 90) groups. Clinical features, complications, and survival rates were compared among the three groups. Risk factors of mortality were subjected to Cox regression analysis.

Results

The N-alone group patients were significantly younger (N alone, M&N, and M alone: 50, 53, and 57 years, respectively), more frequently male (54.3%, 52.6%, and 37.8%), and had a low body mass index (BMI, 23.1, 27.1, and 26.7 kg/m²) and FIB-4 index (1.20, 1.46, and 2.10). Hypopituitarism (5.4%) and hypothyroidism (7.6%) were significantly observed in the N-alone group. Hepatocellular carcinoma (HCC) developed in 0.0%, 4.2%, and 3.5% of the cases, and extrahepatic malignancies in 6.8%, 8.4%, and 4.7% of the cases, respectively, with no significant differences. The cardiovascular event rate was significantly higher in the M-alone group (1, 37, and 11 cases, P < 0.01). Survival rates were similar among the three groups. Risk factors for mortality were age and BMI in the N-alone group; age, HCC, alanine transaminase, and FIB-4 in the M&N group; and FIB-4 in the M-alone group.

Conclusion

Different risk factors for mortality may exist among the FLD groups.

Two-Step Strategy, FIB-4 Followed by Magnetic Resonance Elastography, for Detecting Advanced Fibrosis in NAFLD

BACKGROUND & AIMS

A two-step strategy combining a serum marker and magnetic resonance elastography (MRE) for detecting advanced fibrosis (stage 3-4) among patients with nonalcoholic fatty liver disease (NAFLD) has been proposed, but its diagnostic accuracy has not been evaluated. In this multicenter study, we aimed to investigate the diagnostic accuracy of a two-step strategy including Fibrosis-4 (FIB-4) followed by MRE.

METHODS

In this multicenter study, 806 patients with biopsy-proven NAFLD who underwent contemporaneous MRE were enrolled and randomly assigned to training and validation cohorts. As a first step, patients with FIB-4 <1.3 were defined as test negative regardless of MRE. As a second step, among patients with FIB-4 ≥1.3, MRE <3.6 and ≥3.6 kPa were defined as test negative and positive. The primary outcome was the diagnostic accuracy for advanced fibrosis comparing MRE alone versus the two-step strategy.

RESULTS

Area under the receiver characteristic curves of MRE alone and the two-step strategy were 0.840 and 0.853 in the training cohort (P = .4) and 0.867 and 0.834 in the validation cohort (P = .2), respectively, and the diagnostic accuracy was comparable between the 2 methods. In the entire cohort, negative predictive value (NPV) and positive predictive value (PPV) of MRE for advanced fibrosis were 92.2% and 73.7%, respectively, whereas NPV at the first and second step and PPV at the second step were 90.9%, 84.4%, and 77.0%, respectively.

CONCLUSIONS

The diagnostic accuracy of the two-step strategy was comparable to MRE and could reduce cost by reducing excessive MRE. Therefore, the two-step strategy could be used as a screening method in a large population.

Metabolic Risk Factors for Hepatocellular Carcinoma in Patients with Nonalcoholic Fatty Liver Disease: A Prospective Study

Non-alcoholic fatty liver disease (NAFLD) is a fast-growing public health problem and predisposes to hepatocellular carcinoma (HCC) in a significant proportion of patients. Metabolic alterations might underlie the progression of NAFLD to HCC, but the magnitudes of risk and population-attributable risk fractions (PAFs) for various metabolic conditions that are associated with HCC risk in patients with NAFLD are unknown. We investigated the associations between metabolic conditions and HCC development in individuals with a prior history of NAFLD. The study included 11,245 participants in the SEER-Medicare database, comprising 1310 NAFLD-related HCC cases and 9835 NAFLD controls. We excluded individuals with competing liver diseases (e.g., alcoholic liver disease and chronic viral hepatitis). Baseline pre-existing diabetes mellitus, dyslipidemia, obesity, hypertension, hypothyroidism, and metabolic syndrome were assessed. Multivariable-adjusted logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). PAFs were also calculated for each metabolic condition. The results show that diabetes (OR = 2.39, 95% CI: 2.04-2.79), metabolic syndrome (OR = 1.73, 95% CI: 1.49-2.01), and obesity (OR = 1.62, 95% CI: 1.43-1.85) were associated with a higher HCC risk in individuals with NAFLD. The highest PAF for HCC was observed for pre-existing diabetes (42.1%, 95% CI: 35.7-48.5), followed by metabolic syndrome (28.8%, 95% CI: 21.7-35.9) and obesity (13.2%, 95% CI: 9.6-16.8). The major predisposing factors for HCC in individuals with NAFLD are diabetes mellitus, metabolic syndrome, and obesity, and their control would be critically important in mitigating the rising incidence of NAFLD-related HCC.

Quantification of DNA methylation for carcinogenic risk estimation in patients with non-alcoholic steatohepatitis

BACKGROUND

In recent years, non-alcoholic steatohepatitis (NASH) has become the main cause of hepatocellular carcinoma (HCC). As a means of improving the treatment of NASH-related HCCs based on early detection, this study investigated the feasibility of carcinogenic risk estimation in patients with NASH.

RESULTS

Normal liver tissue (NLT), non-cancerous liver tissue showing histological findings compatible with non-alcoholic fatty liver from patients without HCC (NAFL-O), non-cancerous liver tissue showing NASH from patients without HCC (NASH-O), non-cancerous liver tissue showing non-alcoholic fatty liver from patients with HCC (NAFL-W), non-cancerous liver tissue showing NASH from patients with HCC (NASH-W) and NASH-related HCC were analyzed. An initial cohort of 171 tissue samples and a validation cohort of 55 tissue samples were used. Genome-wide DNA methylation screening using the Infinium HumanMethylation450 BeadChip and DNA methylation quantification using high-performance liquid chromatography (HPLC) with a newly developed anion-exchange column were performed. Based on the Infinium assay, 4050 CpG sites showed alterations of DNA methylation in NASH-W samples relative to NLT samples. Such alterations at the precancerous NASH stage were inherited by or strengthened in HCC samples. Receiver operating characteristic curve analysis identified 415 CpG sites discriminating NASH-W from NLT samples with area under the curve values of more than 0.95. Among them, we focused on 21 CpG sites showing more than 85% specificity, even for discrimination of NASH-W from NASH-O samples. The DNA methylation status of these 21 CpG sites was able to predict the coincidence of HCC independently from histopathological findings such as ballooning and fibrosis stage. The methylation status of 5 candidate marker CpG sites was assessed using a HPLC-based system, and for 3 of them sufficient sensitivity and specificity were successfully validated in the validation cohort. By combining these 3 CpG sites including the ZC3H3 gene, NAFL-W and NASH-W samples from which HCCs had already arisen were confirmed to show carcinogenic risk with 95% sensitivity in the validation cohort.

CONCLUSIONS

After a further prospective validation study using a larger cohort, carcinogenic risk estimation in liver biopsy specimens of patients with NASH may become clinically applicable using this HPLC-based system for quantification of DNA methylation.

Hepatocellular Carcinoma in Non-alcoholic Fatty Liver Disease: Current Progresses and Challenges

The rising global prevalence of metabolic diseases has increased the prevalence of non-alcoholic fatty liver disease (NAFLD), leading to an increase in cases of NAFLD-related hepatocellular carcinoma (HCC). To provide an updated literature review detailing epidemiology, risk factors, pathogenic pathways, and treatment strategies linked to NAFLD-related HCC, we conducted a literature search on PubMed from its inception to December 31, 2021. About 25% of the global population suffers from NAFLD. The annual incidence of HCC among NAFLD patients is approximately 1.8 per 1,000 person-years. Older age, male sex, metabolic comorbidities, unhealthy lifestyle habits (such as smoking and alcohol consumption), physical inactivity, genetic susceptibility, liver fibrosis, and degree of cirrhosis in NAFLD patients are important risk factors for NAFLD-related HCC. Therefore, low-calorie diet, moderate-intensity exercise, treatment of metabolic comorbidities, and cessation of smoking and alcohol are the main measures to prevent NAFLD-related HCC. In addition, all patients with advanced NAFLD-related fibrosis or cirrhosis should be screened for HCC. Immune suppression disorders and changes in the liver microenvironment may be the main pathogenesis of NAFLD-related HCC. Hepatic resection, liver transplantation, ablation, transarterial chemoembolization, radiotherapy, targeted drugs, and immune checkpoint inhibitors are used to treat NAFLD-related HCC. Lenvatinib treatment may lead to better overall survival, while immune checkpoint inhibitors may lead to worse overall survival. Given the specific risk factors for NAFLD-related HCC, primary prevention is key. Moreover, the same treatment may differ substantially in efficacy against NAFLD-related HCC than against HCC of other etiologies.

Review article: the epidemiologic burden of non-alcoholic fatty liver disease across the world

BACKGROUND

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing in parallel with obesity and type 2 diabetes.

AIM

To review the global epidemiology of NAFLD METHODS: We retrieved articles from PubMed using search terms of NAFLD, epidemiology, prevalence, incidence, and comorbidities.

RESULTS

Over 250 articles were reviewed. In 2016, the global NAFLD prevalence was 25%; this increased to >30% in 2019. Prevalence in Asia, Latin America and Middle East-North Africa (MENA) was 30.8%, 34.5% and 42.6%, respectively. Prevalence increased with age. Although prevalence was higher in men, prevalence in post-menopausal women was similar. NAFLD prevalence was higher in certain subpopulations, especially among the obese and those with metabolic syndrome (MS). However, the prevalence of lean NAFLD was 11.2%. The global prevalence of non-alcoholic steatohepatitis (NASH) is estimated between 2% and 6% in the general population. Approximately 7% of patients with NAFLD have advanced fibrosis; rates were between 21% and 50% among patients with NASH. Overall mortality related to NAFLD was 15-20 per 1000 person-years, and increased substantially in patients with NASH, especially in those with components of MS. Recent data suggest mortality/morbidity from NAFLD is increasing globally but NAFLD awareness remains low among patients and healthcare providers.

CONCLUSIONS

NAFLD poses a global public health problem with a very high disease burden in Asia, MENA and Latin America. Research is needed to better quantify the full impact of NAFLD and to develop strategies to improve awareness and risk stratification.

Two differentially methylated region networks in nonalcoholic fatty liver disease, viral hepatitis, and hepatocellular carcinoma

Background

We previously reported that two differentially methylated region (DMR) networks identified by DMR and co-methylation analyses are strongly correlated with the fibrosis stages of nonalcoholic fatty liver disease (NAFLD). In the current study, we examined these DMR networks in viral hepatitis and hepatocellular carcinoma (HCC).

Methods

We performed co-methylation analysis of DMRs using a normal dataset (GSE48325), two NAFLD datasets (JGAS000059 and GSE31803), and two HCC datasets (GSE89852 and GSE56588). The dataset GSE60753 was used for validation.

Results

One DMR network was clearly observed in viral hepatitis and two HCC populations. Methylation levels of genes in this network were higher in viral hepatitis and cirrhosis, and lower in HCC. Fatty acid binding protein 1 (FABP1), serum/glucocorticoid regulated kinase 2 (SGK2), and hepatocyte nuclear factor 4 α (HNF4A) were potential hub genes in this network. Increased methylation levels of the FABP1 gene may be correlated with reduced protection of hepatocytes from oxidative metabolites in NAFLD and viral hepatitis. The decreased methylation levels of SGK2 may facilitate the growth and proliferation of HCC cells. Decreased methylation levels of HNF4A in HCC may be associated with tumorigenesis. The other DMR network was observed in NAFLD, but not in viral hepatitis or HCC. This second network included genes involved in transcriptional regulation, cytoskeleton organization, and cellular proliferation, which are specifically related to fibrosis and/or tumorigenesis in NAFLD.

Conclusions

Our results suggest that one DMR network was associated with fibrosis and tumorigenesis in both NAFLD and viral hepatitis, while the other network was specifically associated with NAFLD progression. Furthermore, FABP1, SGK2, and HNF4A are potential candidate targets for the prevention and treatment of HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02360-4.

MAFLD: Renovation of clinical practice and disease awareness of fatty liver

Recently, international expert panels have proposed a new definition of fatty liver: metabolic dysfunction-associated fatty liver disease (MAFLD). MAFLD is not just a simple renaming of non-alcoholic fatty liver disease (NAFLD). The unique feature of MAFLD is the inclusion of metabolic dysfunctions, which are high-risk factors for events. In addition, MAFLD is independent of alcohol intake and the co-existing causes of liver disease. This new concept of MAFLD may have a widespread impact on patients, medical doctors, medical staff, and various stakeholders regarding fatty liver. Thus, MAFLD may renovate clinical practice and disease awareness of fatty liver. In this review, we introduce the definition of and rationale for MAFLD. We further describe representative cases showing how the diagnostic processes differ between MAFLD and NAFLD. We also summarize recent studies comparing MAFLD with NAFLD and discuss the impact of MAFLD on clinical trials, Japanese populations, and disease awareness.

MAFLD enhances clinical practice for liver disease in the Asia-Pacific region

Fatty liver is now a major cause of liver disease in the Asia-Pacific region. Liver diseases in this region have distinctive characteristics. First, fatty liver is frequently observed in lean/normal-weight individuals. However, there is no standard definition of this unique phenotype. Second, fatty liver is often observed in patients with concomitant viral hepatitis. The exclusion of viral hepatitis from non-alcoholic fatty liver disease limits its value and detracts from the investigation and holistic management of coexisting fatty liver in patients with viral hepatitis. Third, fatty liver-associated hepatocellular carcinoma (HCC) is generally categorized as non-B non-C HCC. Fourth, the population is aging rapidly, and it is imperative to develop a practicable, low-intensity exercise program for elderly patients. Fifth, most patients and nonspecialized healthcare professionals still lack an awareness of the significance of fatty liver both in terms of intrahepatic and extrahepatic disease and cancer. Recently, an international expert panel proposed a new definition of fatty liver: metabolic dysfunction-associated fatty liver disease (MAFLD). One feature of MAFLD is that metabolic dysfunction is a prerequisite for diagnosis. Pertinent to regional issues, MAFLD also provides its diagnostic criteria in lean/normal-weight individuals. Furthermore, MAFLD is independent of any concomitant liver disease, including viral hepatitis. Therefore, MAFLD may be a more suitable definition for fatty liver in the Asia-Pacific region. In this review, we introduce the regional characteristics of fatty liver and discuss the advantages of MAFLD for improving clinical practice for liver disease in the region.

Outcomes of Liver Resection for Metabolic Dysfunction-Associated Fatty Liver Disease or Chronic Hepatitis B-Related HCC

AIMS

This study aims to determine differences in severity of background liver disease at hepatocellular carcinoma (HCC) diagnosis and long-term survival outcomes among patients undergoing liver resection for HCC in the background of metabolic dysfunction-associated fatty liver disease (MAFLD) compared to chronic hepatitis B (CHB) alone or concurrent CHB (CHB/MAFLD).

METHODS

Patient demographics and comorbidities, clinicopathologic data, perioperative and long-term outcomes among patients who underwent liver resection for HCC were reviewed. Overall and recurrence-free survival were calculated with the Kaplan-Meier method, with the values compared using the log-rank test.

RESULTS

From January 2014 to December 2018, 1325 patients underwent potential curative liver resection of HCC; 67 (5.0%), 176 (13.3%), and 1082 (81.7%) patients had MAFLD alone, CHB concurrent with MAFLD, and CHB alone, respectively. At HCC diagnosis, fewer MAFLD patients had cirrhosis, alpha fetoprotein concentration ≥ 400 ng/mL, tumor size ≥ 5 cm, mulinodular, microvascular invasion, receiving major hepatectomy, and receiving adjuvant transarterial chemoembolization. After a median follow-up of 47 months after liver resection, MAFLD (or MAFLD plus CHB/MAFLD) patients had significantly higher overall and recurrence-free survival than CHB patients before or after propensity score analysis (all P<0.05).

CONCLUSION

Patients with HCC in the setting of MAFLD have less-severe background liver disease at HCC diagnosis and better long-term survival after curative liver resection compared to counterparts with CHB/MAFLD or CHB.

Epidemiology of non-alcoholic fatty liver disease and hepatocellular carcinoma

The prevalence of hepatocellular carcinoma (HCC) is increasing worldwide, whereas that of most other cancers is decreasing. Non-alcoholic fatty liver disease (NAFLD), which has increased with the epidemics of obesity and type 2 diabetes, increases the risk of HCC. Interestingly, NAFLD-associated HCC can develop in patients with or without cirrhosis. A lack of awareness about NAFLD-related HCC has led to delays in diagnosis. Therefore, a large number of patients with HCC are diagnosed with advanced-stage HCC with low 5-year survival. In this context, increasing awareness of NAFLD and NAFLD-related HCC may lead to earlier diagnosis and more effective interventions.

White Adipose Tissue Autophagy and Adipose-Liver Crosstalk Exacerbate Nonalcoholic Fatty Liver Disease in Mice

BACKGROUND & AIMS

Although nonalcoholic fatty liver disease (NAFLD) is closely associated with obesity, the role of adipose tissue in NAFLD is not well-understood. Because autophagy has been reported to be involved in the degradation of lipid droplets, we investigated the role of adipose tissue autophagy in the liver pathogenesis of NAFLD.

METHODS

C57BL/6J mice and adipocyte-specific Atg7-knockout mice (Adipoq-Atg7 KO mice) were fed a high-fat diet (HFD).

RESULTS

HFD feeding for up to 4 months increased both inguinal and epididymal white adipose tissue (iWAT and eWAT, respectively; the former represents subcutaneous fat, and the latter represents visceral fat) in mice. After HFD feeding, autophagy flux in both types of white adipose tissue was increased, and the levels of Rubicon, a negative autophagy regulator, were decreased, suggesting autophagy promotion. Adipoq-Atg7 KO mice exhibited suppressed autophagy in both iWAT and eWAT. Adipocyte-specific Atg7 KO enhanced HFD-induced iWAT hypertrophy. On the other hand, eWAT levels in Adipoq-Atg7 KO mice were increased after 1 month of HFD feeding but decreased after 4 months of HFD feeding compared with those in wild-type controls. Cleaved caspase 3 and JNK pathway protein expression in eWAT was increased without cytokine elevation in Adipoq-Atg7 KO mice fed an HFD compared with wild-type mice fed an HFD. Adipocyte-specific Atg7 KO decreased serum free fatty acid levels and ameliorated HFD-induced steatosis, liver inflammation, and fibrosis.

CONCLUSIONS

Autophagy was enhanced in the white adipose tissues of mice fed an HFD. Autophagy inhibition in white adipose tissues ameliorated the liver pathology of NAFLD via adipose-liver crosstalk.

The Current View of Nonalcoholic Fatty Liver Disease-Related Hepatocellular Carcinoma

Simple Summary

The incidence of nonalcoholic fatty liver disease (NAFLD)-related hepatocellular carcinoma (HCC) is increasing. However, an effective screening or surveillance method is not established. Recently, the NAFLD/nonalcoholic steatohepatitis (NASH) guidelines of Japan were revised to incorporate new strategies and evidence for the management and surveillance of NAFLD/NASH. Advanced fibrosis and lifestyle-related and metabolic comorbidities, especially obesity and diabetes mellitus, are associated with HCC development. At the first screening, serum markers of hepatic fibrosis (hyaluronic acid, type IV collagen 7S, and mac-2 binding protein), or the fibrosis (FIB)-4 index or the nonalcoholic fatty liver disease fibrosis score (NFS), or a platelet count should be evaluated. When liver fibrosis is indicated, consultation with a gastroenterology specialist should be considered for the second screening. The risk of HCC should be stratified using the FIB-4 index or the NFS. Liver stiffness should be measured using vibration-controlled transient elastography in those at intermediate or high risk. Blood tests and imaging should be performed every 6–12 months in patients with advanced fibrosis for HCC surveillance. We review here what is known about NAFLD-HCC and provide perspectives for future research.

Abstract

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome and can develop into hepatocellular carcinoma (HCC). The incidence of NAFLD-related HCC, which is accompanied by life-threatening complications, is increasing. Advanced fibrosis and lifestyle-related and metabolic comorbidities, especially obesity and diabetes mellitus, are associated with HCC development. However, HCC is also observed in the non-cirrhotic liver. Often, diagnosis is delayed until the tumor is relatively large and the disease is advanced; an effective screening or surveillance method is urgently required. Recently, the NAFLD/nonalcoholic steatohepatitis (NASH) guidelines of Japan were revised to incorporate new strategies and evidence for the management and surveillance of NAFLD/NASH. Fibrosis must be tested for noninvasively, and the risk of carcinogenesis must be stratified. The treatment of lifestyle-related diseases is expected to reduce the incidence of NAFLD and prevent liver carcinogenesis.