The progress of autoimmune hepatitis research and future challenges

Autoimmune Hepatitis and Vitamin D Deficiency: A Nationwide Perspective

BACKGROUND

Vitamin D deficiency is linked to worse outcomes in patients with chronic liver diseases (CLD). However, data in patients with autoimmune hepatitis (AIH) remain limited.

AIMS

We aimed to assess the impact of vitamin D deficiency on the outcomes of individuals with AIH.

METHODS

This retrospective cohort study used the TriNetX research network to identify patients with AIH. Patients were matched using propensity score matching and stratified to sufficient vitamin D levels (e.g., 25 (OH) D3 ≥ 30 ng/mL), vitamin D insufficiency (25 (OH) D3: 20-29.9 ng/mL) and vitamin D deficiency (e.g., 25 (OH) D3 < 20 ng/mL). The primary outcome was the all-cause mortality among adult patients with AIH. Secondary outcomes included decompensated liver cirrhosis, acute hepatic failure, liver transplantation (LT), all-cause hospitalizations and all-cause critical care admissions.

RESULTS

A total of 1288 AIH patients with vitamin D deficiency were identified and propensity matched with 1288 patients with normal vitamin D levels. Patients with vitamin D deficiency had significantly increased odds for all-cause mortality compared to those with normal levels (adjusted odds ratio (aOR) = 3.2, 95%CI: 2.3-4.48). Patients with vitamin D deficiency were at increased odds of all-cause hospitalizations (aOR = 2.37, 95%CI: 1.97-2.84), critical care unit admissions (aOR = 2.8, 95%CI: 2.21-3.71), decompensated liver cirrhosis (aOR = 2.74, 95%CI: 2.13-3.54), acute hepatic failure (aOR = 3.11, 95%CI: 2.09-4.62) and LT (aOR = 3.47, 95%CI: 1.71-7.04), as compared to those with normal vitamin D levels.

CONCLUSION

This cohort study showed significantly increased odds for all-cause mortality in AIH patients with vitamin D deficiency. Vitamin D deficiency in patients with AIH was associated with increased likelihood of hospitalisation, decompensated liver cirrhosis, acute liver failure and LT.

Mesenchymal Stem Cell-Derived Exosomes: Emerging as a Promising Cell-Free Therapeutic Strategy for Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is an immune-mediated liver disease that currently faces limited treatment options. In its advanced stages, AIH can progress to liver fibrosis and cirrhosis. Recent research has increasingly focused on cell-free therapies, particularly the use of mesenchymal stem cell (MSC)-derived exosomes (Exos), which have shown promise in treating autoimmune diseases, including AIH. MSC-Exos, as microvesicles with low immunogenicity, high safety, and permeability, can deliver RNA, DNA, proteins, lipids, and various drugs for disease treatment, showing promising clinical application prospects. This review provides a comprehensive summary of the current research on MSC-Exos in the treatment of autoimmune hepatitis (AIH) and explores the underlying molecular mechanisms involved. It highlights the significant regulatory effects of MSC-Exos on immune cells and their ability to modify the microenvironment, demonstrating anti-inflammatory and anti-fibrotic properties while promoting liver regeneration. Additionally, this review also discusses potential challenges and future strategies for advancing Exo-based therapies in the treatment of AIH.

The significance of gut microbiota in the etiology of autoimmune hepatitis: a narrative review

Autoimmune hepatitis (AIH) is a chronic inflammatory disease of the liver that is mediated by autoimmunity and has complex pathogenesis. Its prevalence has increased globally. Since the liver is the first organ to be exposed to harmful substances, such as gut-derived intestinal microbiota and its metabolites, gut health is closely related to liver health, and the "liver-gut axis" allows abnormalities in the gut microbiota to influence the development of liver-related diseases such as AIH. Changes in the composition of the intestinal microbiota and its resultant disruption of the intestinal barrier and microbial transport are involved in multiple ways in the disruption of immune homeostasis and inflammation, thereby influencing the development of AIH. In terms of the mechanisms involved in immune, the gut microbiota or its metabolites, which is decreased in secondary bile acids, short-chain fatty acids (SCFAs), and polyamines, and increased in lipopolysaccharide (LPS), branched-chain amino acids (BCAA), tryptophan metabolite, amino acid, and bile acid, can disrupt immune homeostasis by activating various immune cells and immune-related signaling pathways, resulting in aberrant activation of the immune system. Clarifying this mechanism has significant clinical implications for the treatment of AIH with drugs that target intestinal microbiota and related signaling pathways. Therefore, this narrative review summarizes the progress in exploring the involvement of gut microbiota in the pathogenesis of AIH, with the aim of helping to improve the precise targeting of therapeutic treatments against AIH for the benefit of clinical AIH treatment.