Complications of Non-Alcoholic Fatty Liver Disease in Extrahepatic Organs

A Mendelian randomization study between chronic periodontitis and non-alcoholic fatty liver disease

BACKGROUND AND OBJECTIVE

Observational studies have suggested a potential association between non-alcoholic fatty liver disease (NAFLD) and chronic periodontitis (CP). However, these studies are prone to confounding factors. The aim of this study was to assess the causal relationship between NAFLD and CP using a two-sample bidirectional Mendelian randomization (MR) analysis method.

METHODS

Datasets of CP and NAFLD were retrieved from the European database, and instrumental variables (IVs) related to exposure were selected for the MR analysis. Sensitivity tests, including heterogeneity and horizontal pleiotropy tests, were conducted to ensure the consistency of the selected IVs, following which the analysis results were visualized.

RESULTS

Genetic variants associated with CP and NAFLD were identified as IVs, and the MR assessment was performed using the summary data (CP: 3046 cases and 195 395 controls; NAFLD: 894 cases and 217 898 controls). CP increased the risk of NAFLD (inverse variance weighted [IVW], b = 0.132 > 0, p = .006 < .05), whereas the reverse was not observed (IVW, b = -0.024 < 0, p = .081 > .05). The sensitivity analysis indicated no heterogeneity or horizontal pleiotropy.

CONCLUSION

The MR analysis suggested that CP could increase the risk of NAFLD among European populations.

Prevalence of Hepatobiliary Manifestations in Inflammatory Bowel Disease: A GRADE Assessed Systematic Review and Meta-Analysis of more than 1.7 Million Patients

BACKGROUND AND AIMS

Inflammatory bowel disease [IBD] comprises an immune-mediated group of chronic gastrointestinal disorders. Patients with IBD may experience extraintestinal manifestations, such as hepatobiliary complications. This meta-analysis aims to assess the prevalence of different hepatic manifestations in IBD patients.

METHODS

For this systematic review and meta-analysis, PubMed, Scopus, Web of Science, and Embase were searched until July 20, 2022, by specifying keywords for IBD, hepatic manifestations, and study type. Full texts of cohort studies in English that examined the prevalence of different hepatic manifestations were included in this study. The primary outcome was the overall prevalence of hepatic manifestations in IBD patients. For the statistical analysis, a proportion by random effect model meta-analysis was performed. The registration number for the protocol of this study in PROSPERO is CRD42022369595.

RESULTS

From the 4421 articles retrieved from the primary search, 118 met the inclusion criteria and were included in the final analysis. After a pooled analysis of 1 729 128 patients, the overall prevalence of hepatic manifestations was 3.49% (95% confidence interval [CI]: 3.31-3.68%; I2: 99.55%). The pooled prevalence of non-alcoholic fatty liver disease in 228 216 patients was 26.1% [95% CI: 22.1-30.2%; I2: 99.018%]. After pooled analysis of 9642 patients, the prevalence of primary sclerosing cholangitis was 1.67% [95% CI: 1.47-1.88%; I2: 99.10%]. The pooled prevalence of biliary stones was 4.1% [95% CI: 3.6-4.7%; I2: 97.43%]. Autoimmune hepatitis (0.51% [95% CI: 0.26-0.75%]; I2: 85.36%) and portal vein thrombosis (0.21% [95% CI: 0.08-0.33%]; I2: 97.95%) are considered as rare manifestations.

CONCLUSION

This study summarizes the prevalence and importance of different hepatic manifestations in IBD patients. These findings are crucial for the management of extraintestinal manifestations, especially hepatic manifestations, in IBD patients.

Current status and future trends of the global burden of MASLD

Metabolic dysfunction-associated steatotic liver disease (MASLD) has emerged as the most common chronic liver disease globally, affecting more than a third of the world's adult population. This comprehensive narrative review summarizes the global incidence and prevalence rates of MASLD and its related adverse hepatic and extrahepatic outcomes. We also discuss the substantial economic burden of MASLD on healthcare systems, thus further highlighting the urgent need for global efforts to tackle this common and burdensome liver condition. We emphasize the clinical relevance of early interventions and a holistic approach that includes public health strategies to reduce the global impact of MASLD.

TGF Beta as a Prognostic Biomarker of COVID-19 Severity in Patients with NAFLD-A Prospective Case-Control Study

Non-alcoholic fatty liver disease (NAFLD), the leading cause of chronic liver disease in Western countries, has been identified as a possible risk factor for COVID-19 severity. However, the immunological mechanisms by which NAFLD exacerbates COVID-19 remain unknown. Transforming growth factor-beta 1 (TGF-β1) has an important immunomodulatory and pro-fibrotic role, which has already been described in NAFLD. However, the role of TGF-β1 in COVID-19 remains unclear, and could also be the pathophysiology link between these two conditions. The aim of this case-control study was to analyze the expression of TGF-β1 in COVID-19 patients depending on the presence of NAFLD and COVID-19 severity. Serum TGF-β1 concentrations were measured in 60 hospitalized COVID-19 patients (30 with NAFLD). NAFLD was associated with higher serum TGF-β1 concentrations that increased with disease severity. Admission TGF-β1 concentrations showed good discriminative accuracy in predicting the development of critical disease and COVID-19 complications (need for advanced respiratory support, ICU admission, time to recovery, development of nosocomial infections and mortality). In conclusion, TGF-β1 could be an efficient biomarker for predicting COVID-19 severity and adverse outcomes in patients with NAFLD.

The Presence of Periodontitis Exacerbates Non-Alcoholic Fatty Liver Disease via Sphingolipid Metabolism-Associated Insulin Resistance and Hepatic Inflammation in Mice with Metabolic Syndrome

Clinical studies have shown that periodontitis is associated with non-alcoholic fatty liver disease (NAFLD). However, it remains unclear if periodontitis contributes to the progression of NAFLD. In this study, we generated a mouse model with high-fat diet (HFD)-induced metabolic syndrome (MetS) and NAFLD and oral P. gingivalis inoculation-induced periodontitis. Results showed that the presence of periodontitis increased insulin resistance and hepatic inflammation and exacerbated the progression of NAFLD. To determine the role of sphingolipid metabolism in the association between NAFLD and periodontitis, we also treated mice with imipramine, an inhibitor of acid sphingomyelinase (ASMase), and demonstrated that imipramine treatment significantly alleviated insulin resistance and hepatic inflammation, and improved NAFLD. Studies performed in vitro showed that lipopolysaccharide (LPS) and palmitic acid (PA), a major saturated fatty acid associated with MetS and NAFLD, synergistically increased the production of ceramide, a bioactive sphingolipid involved in NAFLD progression in macrophages but imipramine effectively reversed the ceramide production stimulated by LPS and PA. Taken together, this study showed for the first time that the presence of periodontitis contributed to the progression of NAFLD, likely due to alterations in sphingolipid metabolism that led to exacerbated insulin resistance and hepatic inflammation. This study also showed that targeting ASMase with imipramine improves NAFLD by reducing insulin resistance and hepatic inflammation.

Tocotrienol in the Management of Nonalcoholic Fatty Liver Disease: A Systematic Review

The increasing burden of nonalcoholic fatty liver disease (NAFLD) requires innovative management strategies, but an effective pharmacological agent has yet to be found. Apart from weight loss and lifestyle adjustments, one isomer of the vitamin E family-alpha-tocopherol-is currently recommended for nondiabetic steatohepatitis patients. Another member of the vitamin E family, tocotrienol (T3), has anti-inflammatory and antioxidant properties that reach beyond those of alpha-tocopherol, making it a potential agent for use in NAFLD management. This systematic review aimed to provide an overview of the effects of T3 supplementation on NAFLD from both clinical and preclinical perspectives. A literature search was performed in October 2022 using PubMed, Scopus and Web of Science. Original research articles reporting NAFLD outcomes were included in this review. The search located 12 articles (8 animal studies and 4 human studies). The literature reports state that T3 isomers or natural mixtures (derived from palm or annatto) improved NAFLD outcomes (liver histology, ultrasound or liver profile). However, the improvement depended on the severity of NAFLD, study period and type of intervention (isomers/mixture of different compositions). Mechanistically, T3 improved lipid metabolism and prevented liver steatosis, and reduced mitochondrial and endoplasmic reticulum stress, inflammation and ultimately liver fibrosis. In summary, T3 could be a potential agent for use in managing NAFLD, pending more comprehensive preclinical and human studies.

Metabolic Associated Fatty Liver Disease as a Risk Factor for the Development of Central Nervous System Disorders

MAFLD/NAFLD is the most ordinary liver disease categorized by hepatic steatosis with the increase of surplus fat in the liver and metabolic liver dysfunction, which is associated with bigger mortality and a high medical burden. An association between MAFLD/NAFLD and central nervous system disorders including psychological disorders has been demonstrated. Additionally, MAFLD/NAFLD has been correlated with various types of neurodegenerative disorders such as amyotrophic lateral sclerosis or Parkinson’s disease. Contrasted to healthy controls, patients with MAFLD/NAFLD have a greater prevalence risk of extrahepatic complications within multiple organs. Dietary interventions have emerged as effective strategies for MAFLD/NAFLD. The PI3K/AKT/mTOR signaling pathway involved in the regulation of Th17/Treg balance might promote the pathogenesis of several diseases including MAFLD/NAFLD. As extrahepatic complications may happen across various organs including CNS, cooperative care with individual experts is also necessary for managing patients with MAFLD/NAFLD.

Heart Uptake of [18F]Fluoro-4-Thia-Oleate in a Non-Alcoholic Fatty Liver Disease Mouse Model

The world-wide high incidence of non-alcoholic fatty liver disease (NAFLD) is of concern for its progression to insulin resistance, steatohepatitis and cardiovascular disease (CVD). The increased uptake of fatty acids in critical organs plays a major role in NAFLD progression. Male Ceacam1−/− mice that develop NAFLD, insulin resistance and CVD on normal chow are a potential model for studying the dysregulation of fatty acid uptake. [18F]fluoro-4-thia-oleate ([18F]FTO) was chosen as a fatty acid reporter because of its higher uptake and retention in the heart in an animal model of CVD. Male wild-type (WT) or Ceacam1−/− mice fasted 4−6 h were administered [18F]FTO i.v., and dynamic PET scans were conducted in an MR/PET small animal imaging system along with terminal tissue biodistributions. Quantitative heart image analysis revealed significantly higher uptake at 35 min in Ceacam1−/− (6.0 ± 1.0% ID/cc) vs. WT (3.9 ± 0.6% ID/cc) mice (p = 0.006). Ex vivo heart uptake/retention (% ID/organ) was 2.82 ± 0.45 for Ceacam1−/− mice vs. 1.66 ± 0.45 for WT mice (p < 0.01). Higher kidney and pancreas uptake/retention in Ceacam1−/− was also evident, and the excretion of [18F]FTO into the duodenum was observed for both WT and Ceacam1−/− mice starting at 10 min. This study suggests that the administration of [18F]FTO as a marker of fatty acid uptake and retention may be an important tool in analyzing the effect of NAFLD on lipid dysregulation in the heart.

All Roads Lead to Cathepsins: The Role of Cathepsins in Non-Alcoholic Steatohepatitis-Induced Hepatocellular Carcinoma

Cathepsins are lysosomal proteases that are essential to maintain cellular physiological homeostasis and are involved in multiple processes, such as immune and energy regulation. Predominantly, cathepsins reside in the lysosomal compartment; however, they can also be secreted by cells and enter the extracellular space. Extracellular cathepsins have been linked to several pathologies, including non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC). NASH is an increasingly important risk factor for the development of HCC, which is the third leading cause of cancer-related deaths and poses a great medical and economic burden. While information regarding the involvement of cathepsins in NASH-induced HCC (NASH-HCC) is limited, data to support the role of cathepsins in either NASH or HCC is accumulating. Since cathepsins play a role in both NASH and HCC, it is likely that the role of cathepsins is more significant in NASH-HCC compared to HCC derived from other etiologies. In the current review, we provide an overview on the available data regarding cathepsins in NASH and HCC, argue that cathepsins play a key role in the transition from NASH to HCC, and shed light on therapeutic options in this context.

Lean/normal-weight metabolic dysfunction-associated fatty liver disease is a risk factor for reflux esophagitis

AIM

Reflux esophagitis is associated with metabolic dysfunction. Recently, fatty liver has been redefined as metabolic dysfunction-associated fatty liver disease (MAFLD). We investigated the impact of MAFLD and its subtypes on the incidence of reflux esophagitis.

METHODS

This multicenter, observational cohort study enrolled 9100 consecutive health-check examinees who underwent esophagogastroduodenoscopy and ultrasonography. All patients were classified into the MAFLD or non-MAFLD group. Based on the Asian cut-off value for body mass index (BMI), the MAFLD group was further classified into the lean/normal-weight (BMI <23 kg/m² ) and overweight/obese (BMI ≥23 kg/m² ) subgroups. The impact of MAFLD and its subtypes on the cumulative incidence of reflux esophagitis was evaluated using multivariable Cox proportional hazards regression analysis.

RESULTS

MAFLD was diagnosed in 26.5% (2416/9100) of patients. Multivariable Cox proportional hazards regression analysis indicated that MAFLD (hazard ratio [HR] 1.2183; 95% confidence interval [CI] 1.0954-1.3550; p = 0.0003), hiatal hernia, and aging were independent risk factors for reflux esophagitis. Stratification analysis indicated that cumulative incidence of reflux esophagitis among patients with MAFLD was significantly higher in the lean/normal-weight than in the overweight/obese group (HR 1.3274; 95% CI 1.0043-1.7547; p = 0.0466). Among various metabolic factors, visceral adiposity was the only independent metabolic risk factor for reflux esophagitis (HR 2.8331; 95% CI 1.0201-7.8691; p = 0.0457) in the lean/normal-weight MAFLD group.

CONCLUSIONS

MAFLD, in particular lean/normal-weight MAFLD, is independent risk factor for reflux esophagitis. Furthermore, visceral adiposity was identified as the most strong metabolic risk factor for reflux esophagitis in lean/normal-weight patients with MAFLD.

Healthcare practitioners' diagnostic and treatment practice patterns of nonalcoholic fatty liver disease in Poland: a cross-sectional survey

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) awareness is low. NAFLD diagnosis and management by gastroenterologists (GEs) and general practitioners (GPs) in Poland were evaluated.

METHODS

RESTORE was an observational, noninterventional, retrospective cross-sectional survey performed among GEs and GPs with at least 3 years' experience. Computer-assisted web interviews were completed. GEs provided information from patient records.

RESULTS

Mean experience was 14.2 (95 GEs) and 22.6 (115 GPs) years. Mean patient numbers with liver disorders consulted per month were 36 (13%; GEs) and 51 (6%; GPs); ~50% were patients with NAFLD. All GEs/GPs used ultrasound; most evaluated transaminases and gamma-glutamyl transferase. More GEs used other imaging techniques and a larger spectrum of laboratory tests than GPs. Physician-identified NAFLD key symptoms were similar for GEs/GPs. GEs noticed less obvious symptoms (abdominal discomfort, drowsiness, fatigability, lack of energy) vs. GPs (abdominal pain/discomfort, dyspepsia). Common comorbidities in NAFLD were similar in GE/GP responses. NAFLD interventions by GEs/GPs (% patients) were diet/lifestyle/pharmacological interventions (54%/59%), diet/lifestyle changes alone (41%/31%) or pharmacological interventions alone (5%/10%). The top three criteria for supportive pharmacological selection were efficacy, tolerability and quality of life improvement for GEs/GPs. The five supportive treatments most commonly prescribed by GEs/GPs were essential phospholipids, ursodeoxycholic acid, timonacic, silybinin/silymarin and ornithine + choline. Information from patient records (n = 380) confirmed GEs responses.

CONCLUSIONS

NAFLD is not a silent disease as physicians and patients reported many, albeit nonspecific, symptoms. This cross-sectional survey provides important insights into clinical management of NAFLD by GEs and GPs in Poland.

Nonalcoholic fatty liver disease is associated with a higher incidence of coeliac disease

BACKGROUND

Recently the incidence of nonalcoholic fatty liver disease (NAFLD) has risen to become the most frequent liver disease worldwide. NAFLD is not a disease limited to the liver, but rather represents a systemic inflammatory disease involving multiple organ systems. Previous studies have suggested an association between NAFLD and coeliac disease, another disease related to inflammation. As the available clinical data is scarce and at least partially contradictory, we aimed at investigating a potential association between NAFLD and celiac disease in outpatients in Germany.

METHODS

Using the Disease Analyzer database featuring data on diagnoses, prescriptions and demographic variables for 7.49 million cases of patients followed in general practices in Germany, we matched a total of 57 336 patients with NAFLD/diagnosed between 2000 and 2015 to a cohort of equal size without NAFLD by age, sex and index year. Incidence of celiac disease was compared between groups within 10 years from the index date.

RESULTS

During the 10-years observation period, we observed a higher incidence of coeliac disease in NAFLD patients compared to patients without NAFLD (11.2 vs. 7.5 cases per 100 000 patients' years). Interestingly, this association was most prominent in men (hazard ratio, 2.02; 95% CI, 1.01-4.04) and patients between 18 and 50 years (hazard ratio, 2.79; 95% CI, 1.12-6.94).

SUMMARY

Our data suggest that NAFLD promotes the development of coeliac disease particularly in young men. This finding argues that coeliac disease should be recognized as another nonliver-related complication of NAFLD and suggests screening of selected NAFLD patients for the presence of coeliac disease.

Prothrombotic and Inflammatory Markers in Elderly Patients with Non-Alcoholic Hepatic Liver Disease before and after Weight Loss: A Pilot Study

Background: Non-alcoholic fatty liver disease (NAFLD) is a pathological condition, ranging from fatty liver to chronic steatohepatitis (NASH), liver cirrhosis, and eventually to hepatocellular carcinoma. Recent findings suggest that patients with NAFLD have an increased risk of cardiovascular events and thromboembolism, which is independent of metabolic diseases that are frequently associated with NAFLD, such as diabetes, hyperlipidemia, and obesity. Methods: We evaluated 30 NAFLD patients, before and after weight loss. Plasma levels of C-reactive protein (CRP), fibrinogen, plasminogen activator inhibitor-1 (PAI-1), von Willebrand factor (VWF), homocysteine, coagulation protein S, Thrombin activable fibrinolysis inhibitor (TAFI), and factor VII (FVII) were assessed to evaluate whether they should be responsible of the prothrombotic state of NAFLD after weight loss. Results: At baseline, patients affected by NAFLD had a significantly higher levels of CRP, fibrinogen, PAI-1, VWF antigen, and FVII levels. After weight reduction, we observed a significant drop of inflammatory and prothrombotic markers, as well as glucometabolic, lipid profile. Conclusion: These findings provide evidence for a link between NAFLD/NASH and thromboembolism. The association seems to be linked with primitive thrombotic state and hypercoagulation due to increased levels of coagulation factors and reduced levels of PAI-1. This hypercoagulation state might explain increased levels of thrombosis and splanchnic thrombosis observed in NASH correlated cirrhosis.