[Autoimmune hepatitis: Immunological diagnosis]

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.

Enhancing Liver Delivery of Gold Nanoclusters via Human Serum Albumin Encapsulation for Autoimmune Hepatitis Alleviation

Peptide-protected gold nanoclusters (AuNCs), possessing exceptional biocompatibility and remarkable physicochemical properties, have demonstrated intrinsic pharmaceutical activity in immunomodulation, making them a highly attractive frontier in the field of nanomedicine exploration. Autoimmune hepatitis (AIH) is a serious autoimmune liver disease caused by the disruption of immune balance, for which effective treatment options are still lacking. In this study, we initially identified glutathione (GSH)-protected AuNCs as a promising nanodrug candidate for AIH alleviating in a Concanavalin A (Con A)-induced mice model. However, to enhance treatment efficiency, liver-targeted delivery needs to be improved. Therefore, human serum albumin (HSA)-encapsulated AuNCs were constructed to achieve enhanced liver targeting and more potent mitigation of Con A-induced elevations in plasma aspartate transaminase (AST), alanine transaminase (ALT), and liver injury in mice. In vivo and in vitro mechanism studies indicated that AuNCs could suppress the secretion of IFN-γ by Con A-stimulated T cells and subsequently inhibit the activation of the JAK2/STAT1 pathway and eventual hepatocyte apoptosis induced by IFN-γ. These actions ultimately protect the liver from immune cell infiltration and damage caused by Con A. These findings suggest that bio-protected AuNCs hold promise as nanodrugs for AIH therapy, with their liver targeting capabilities and therapeutic efficiency being further improved via rational surface ligand engineering.

Pien Tze Huang alleviates Concanavalin A-induced autoimmune hepatitis by regulating intestinal microbiota and memory regulatory T cells

BACKGROUND

Traditional Chinese medicine has used the drug Pien Tze Huang (PTH), a classic prescription, to treat autoimmune hepatitis (AIH). However, the precise mode of action is still unknown.

AIM

To investigate the mechanism of PTH in an AIH mouse model by determining the changes in gut microbiota structure and memory regulatory T (mTreg) cells functional levels.

METHODS

Following induction of the AIH mouse model induced by Concanavalin A (Con A), prophylactic administration of PTH was given for 10 d. The levels of mTreg cells were measured by flow cytometry, and intestinal microbiota was analyzed by 16S rRNA analysis, while western blotting was used to identify activation of the toll-like receptor (TLR)2, TLR4/nuclear factor-κB (NF-κB), and CXCL16/CXCR6 signaling pathways.

RESULTS

In the liver of mice with AIH, PTH relieved the pathological damage and reduced the numbers of T helper type 17 cells and interferon-γ, tumor necrosis factor-alpha, interleukin (IL)-1β, IL-2, IL-6, and IL-21 expression. Simultaneously, PTH stimulated the abundance of helpful bacteria, promoted activation of the TLR2 signal, which may enhance Treg/mTreg cells quantity to produce IL-10, and suppressed activation of the TLR4/NF-κB and CXCL16/CXCR6 signaling pathways.

CONCLUSION

PTH regulates intestinal microbiota balance and restores mTreg cells to alleviate experimental AIH, which is closely related to the TLR/CXCL16/CXCR6/NF-κB signaling pathway.

Seronegative Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is a relatively rare liver disease with varying worldwide incidence of from 0.7 to 2 per 100,000 people. It is characterized by the presence of auto-antibodies. However, an average of 10% of AIH cases have AIH symptoms and pathology but lack autoimmune serology. For such seronegative AIH (snAIH) cases, there is currently no established diagnostic algorithm for diagnosis. and improper or delayed diagnosis of snAIH can lead to no or inappropriate treatment that results in progression to fulminant hepatitis or cirrhosis. This review aims to review the current literature and to present an update of seronegative autoimmune hepatitis, including its pathophysiology, clinical presentation, methods of diagnosis, and treatment in order to increase awareness and emphasize the necessity for timely management.

A Novel Presentation of Autoimmune Hepatitis with IgG1 Elevation

Autoimmune hepatitis (AIH) is a common and debilitating pathology that has acute, subacute, and chronic presentation, requiring prompt diagnosis and early intervention. Several serologic markers are found to be associated with the pathogenesis and progression of autoimmune hepatitis, most notably antinuclear antibodies and anti-smooth muscle antibodies [Front Immunol. 2018;9:609]. In addition, AIH is also characterized by the elevation of gamma globulin levels, mainly immunoglobulin G (IgG) [World J Gastroenterol. 2015;21(1):60-83]. Although the literature has well established the presence of increased IgG levels in AIH, few studies have evaluated the subtypes of IgG and their differential levels associated with AIH. Here, we present a rare case of AIH that lacks the common serologic markers but instead reveals an elevation in IgG1 level. Our patient was subsequently placed on corticosteroids, and her symptoms quickly resolved. We intend to introduce this case to the medical community in the hope of aiding in the proper diagnosis and timely intervention of subsequent cases with similar presentations.

Chinese medicine in the treatment of autoimmune hepatitis: Progress and future opportunities

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease occurring in individuals of all ages with a higher incidence in females and characterized by hypergammaglobulinemia, elevated serum autoantibodies and histological features of interface hepatitis. AIH pathogenesis remains obscure and still needs in‐depth study, which is likely associated with genetic susceptibility and the loss of immune homeostasis. Steroids alone and in combination with other immunosuppressant agents are the primary choices of AIH treatment in the clinic, whereas, in some cases, severe adverse effects and disease relapse may occur. Chinese medicine used for the treatment of AIH has proven its merits over many years and is well tolerated. To better understand the pathogenesis of AIH and to evaluate the efficacy of novel therapies, several animal models have been generated to recapitulate the immune microenvironment of patients with AIH. In the current review, we summarize recent advances in the study of animal models for AIH and their application in pharmacological research of Chinese medicine‐based therapies and also discuss current limitations. This review aims to provide novel insights into the discovery of Chinese medicine‐originated therapies for AIH using cutting‐edge animal models.

Metabolomic Signatures of Autoimmune Hepatitis in the Development of Cirrhosis

Objectives: Autoimmune hepatitis (AIH) can progress into severe outcomes, i.e., decompensated cirrhosis, from remarkable and persistent inflammation in the liver. Considering the energy-expending nature of inflammation, we tried to define the metabolomics signatures of AIH to uncover the underlying mechanisms of cirrhosis development and its metabolic biomarkers. Methods: Untargeted metabolomics analysis was performed on sera samples from 79 AIH patients at the stages (phenotypes) of non-cirrhosis (n = 27), compensated cirrhosis (n = 22), and decompensated cirrhosis (n = 30). Pattern recognition was used to find unique metabolite fingerprints of cirrhosis with or without decompensation. Results: Out of the 294 annotated metabolites identified, 2 metabolic fingerprints were found associated with the development of cirrhosis (independent of the decompensated state, 42 metabolites) and the evolution of decompensated cirrhosis (out of 47 metabolites), respectively. The cirrhosis-associated fingerprints (eigenmetabolite) showed better capability to differentiate cirrhosis from non-cirrhosis patients than the aminotransferase-to-platelet ratio index. From the metabolic fingerprints, we found two pairs of metabolites (Mesobilirubinogen/6-Hydroxynicotinic acid and LysoPA(8:0/0:0)/7alpha-Hydroxycholesterol) calculated as ratio of intensities, which revealed robust abilities to identify cirrhosis or predict decompensated patients, respectively. These phenotype-related fingerprint metabolites featured fundamental energy supply disturbance along with the development of AIH cirrhosis and progression to decompensation, which was characterized as increased lipolysis, enhanced proteolysis, and increased glycolysis. Conclusions: Remodeling of metabolism to meet the liver inflammation-related energy supply is one of the key signatures of AIH in the development of cirrhosis and decompensation. Therefore, drug regulation metabolism has great potential in the treatment of AIH.

Deficiency of O-linked-glycosylation regulates activation of T cells and aggravates Concanavalin A-induced liver injury

OBJECTIVE

Protein glycosylation is involved in immunological recognition and immune cell activation. The role of O-glycosylation in Concanavalin A (Con A)-induced autoimmune hepatitis (AIH) was elucidated in the present study.

METHODS

Mice were intravenously injected with Con A (10 mg/kg) to establish an AIH mouse model. Here, 24 h prior to administration of Con A, experimental mice were intragastrically administrated with O-glycosylation inhibitor (benzyl-α-GalNAc) at doses of 1 and 5 mg/kg, respectively, while control mice were administrated with the same volume of saline. Before and after administration of Con A for 6 and 12 h, mice were sacrificed and their plasma and livers were collected to score liver injury. Peripheral blood, spleen, and thymus were collected for flow cytometry analysis. The expression levels of neutrophilic alkaline phosphatase-3 (NALP3) and NALP6 in liver were evaluated as well.

RESULTS

Pre-treatment with benzyl-α-GalNAc increased the serum transaminase levels and induced more infiltration and necrosis in livers of Con A administrated mice. The levels of some pro-inflammation cytokines also increased in administrated mice. In addition, pretreatment with benzyl-α-GalNAc up-regulated the expression levels of NALP3 and NALP6. And benzyl-α-GalNAc inhibited the levels of apoptosis of thymus cells and influenced activation of T cells in peripheral blood and spleen of Con A administrated mice, especially that accelerated the physiological progression of CD4⁺CD25^-CD69⁺ subset.

CONCLUSION

The present research demonstrated that benzyl-α-GalNAc aggravated Con A-induced AIH, and the role of the O-glycosylation inhibitor as the aggravation may be related to regulation of the levels of cytokines, as well as influencing proliferation of T cells.