The Role of Non-Alcoholic Fatty Liver Disease in Infections

Metabolic Dysfunction-associated Fatty Liver Disease: An Urgent Call for Global Action

There has been an exponential increase in the global prevalence of fatty liver disease in recent years in association with the obesity pandemic worldwide. 'Metabolic dysfunction-associated fatty liver disease', the new terminology adopted by an international panel of experts in 2020 to largely replace the old term 'non-alcoholic fatty liver disease', has now been accepted by most hepatologists and diabetologists across the globe. The term metabolic dysfunction-associated fatty liver disease was created to better reflect the metabolicand liver-specific manifestations and complications of fatty liver disease. It is important to disseminate our current understanding of this enigmatic disease among the global scientific fraternity. Recent publications, including articles from the latest issue of Endocrinology & Metabolism Clinics of North America, are attempting to fill this knowledge gap.

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.

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.