Autoimmune Liver Injury Research Articles

Succinic Acid Ameliorates Concanavalin A-Induced Hepatitis by Altering the Inflammatory Microenvironment and Expression of BCL-2 Family Proteins.

Autoimmune hepatitis (AIH) is a severe immune-mediated inflammatory liver disease that currently lacks feasible drug treatment methods. Our study aimed to evaluate the protective effect of succinic acid against AIH and provide a reliable method for the clinical treatment of AIH. We performed an in vivo study of the effects of succinic acid on concanavalin A (ConA)-induced liver injury in mice. We examined liver transaminase levels, performed hematoxylin and eosin (HE) staining, and observed apoptotic phenotypes in mice. We performed flow cytometry to detect changes in the number of neutrophils and monocytes, and used liposomes to eliminate the liver Kupffer cells and evaluate their role. We performed bioinformatics analysis, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and western blotting to detect mitochondrial apoptosis-induced changes in proteins from the B-cell lymphoma 2(Bcl-2) family. Succinic acid ameliorated ConA-induced AIH in a concentration-dependent manner, as reflected in the survival curve. HE and TUNEL staining and terminal deoxynucleotidyl transferase dUTP nick end labeling revealed decreased alanine transaminase and aspartate aminotransferase levels, and reduced liver inflammation and apoptosis. RT-qPCR and enzyme-linked immunosorbent assay revealed that succinic acid significantly reduced liver pro-inflammatory cytokine levels. Flow cytometry revealed significantly decreased levels of liver neutrophils. Moreover, the protective effect of succinic acid disappeared after the Kupffer cells were eliminated, confirming their important role in the effect. Bioinformatics analysis, RT-qPCR, and western blotting showed that succinic acid-induced changes in proteins from the Bcl-2 family involved mitochondrial apoptosis, indicating the molecular mechanism underlying the protective effect of succinic acid. Succinic acid ameliorated ConA-induced liver injury by regulating immune balance, inhibiting pro-inflammatory factors, and promoting anti-apoptotic proteins in the liver. This study provides novel insights into the biological functions and therapeutic potential of succinic acid in the treatment of autoimmune liver injury.

M1 macrophage-derived exosomes promote autoimmune liver injury by transferring long noncoding RNA H19 to hepatocytes.

Exosomes mediate intercellular communication by transmitting active molecules. The function of long noncoding RNA (lncRNA) H19 in autoimmune liver injury is unclear. Concanavalin A (ConA)-induced liver injury is well-characterized immune-mediated hepatitis. Here, we showed that lncRNA H19 expression was increased in the liver after ConA treatment, accompanied by increased exosome secretion. Moreover, injection of AAV-H19 aggravated ConA-induced hepatitis, with an increase in hepatocyte apoptosis. However, GW4869, an exosome inhibitor, alleviated ConA-induced liver injury and inhibited the upregulation of lncRNA H19. Intriguingly, lncRNA H19 expression in the liver was significantly downregulated, after macrophage depletion. Importantly, the lncRNA H19 was primarily expressed in type I macrophage (M1) and encapsulated in M1-derived exosomes. Furthermore, H19 was transported from M1 to hepatocytes via exosomes, and exosomal H19 dramatically induced hepatocytes apoptosis both in vitro and vivo. Mechanistically, H19 upregulated the transcription of hypoxia-inducible factor-1 alpha (HIF-1α), which accumulated in the cytoplasm and mediated hepatocyte apoptosis by upregulating p53. M1-derived exosomal lncRNA H19 plays a pivotal role in ConA-induced hepatitis through the HIF-1α-p53 signaling pathway. These findings identify M1 macrophage-derived exosomal H19 as a novel target for the treatment of autoimmune liver diseases.

Oroxylin A inhibited autoimmune hepatitis-induced liver injury and shifted Treg/Th17 balance to Treg differentiation.

Autoimmune hepatitis (AIH) is a kind of autoimmune disease mediated by T cells, and its incidence is gradually increasing in the world. Oroxylin A (OA) is one of the major bioactive flavonoids that has been reported to inhibit inflammatory. Here, an AIH model of mouse was induced by Concanavalin A (Con A). It found that serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were decreased in mice with the treatment of OA. Hematoxylin-eosin staining showed that the liver injury was attenuated by OA, and TUNEL staining indicated that the cells apoptosis of liver was weakened in mice with OA treatment. ELISA analysis of cytokines and chemokines suggested that OA reduced the expression of IL-6, IL-17A, chemokine ligand 2 (CCL2), C-X-C motif chemokine ligand 1 (CXCL1) and CXCL10, but promoted the expression of IL-10 and TGF-β in mice. The mRNA levels of Il-17a in liver and spleen tissues were also significantly decreased, on the contrary, the mRNA levels of Il-10 in liver and spleen tissues were increased. The proportion of Treg/Th17 detected by flow cytometry revealed that OA promoted the differentiation of Treg and inhibited the differentiation of Th17 both in the liver and spleen. The results of this study demonstrated the inhibitory effects of OA on AIH-induced liver injury and the inflammatory response of AIH, and revealed that OA affected the balance of Treg/Th17 and shifted the balance toward Treg differentiation. It provided new potential drugs for the prevention of AIH.

S3093 Monotherapy for Multiple Autoimmune Diseases: The Novel Use of Ofatumumab for Concurrent Multiple Sclerosis and Autoimmune Hepatitis

Introduction: Autoimmune hepatitis (AIH) is a rare acute or chronic inflammatory liver disease, that can be associated with a variety of extrahepatic disorders, such as multiple sclerosis (MS). AIH has been reported both during and after treatment with immunomodulatory drugs for MS, such as interferon-beta and steroids, with its incidence in MS being 10-fold higher than the general population. Typically, those patients are treated with steroids and azathioprine as the first line of treatment according to AIH guidelines. However, in comparison to newer disease-modifying therapies (DMTs) for MS, azathioprine is less effective and requires further study. Notably, several studies have suggested a role for B-cell-driven autoimmune liver injury in AIH, and there have been reports of refractory AIH being successfully treated with rituximab, an anti-CD20 monoclonal antibody. Based on these results and the well-known role of B-cells in the underlying pathophysiology of MS, we postulated that anti-CD20 therapy may be effective in treating patients with concurrent MS and AIH, thereby helping to limit steroid duration and avoid the use of azathioprine. Case Description/Methods: We report the case of a 49-year-old previously healthy female who presented with symptoms and magnetic resonance imaging (MRI) findings consistent with relapsing-remitting MS (RRMS). On routine labs at initial presentation, she was incidentally found to have ALT/AST in the 500's range. An extensive work-up was completed, including a liver biopsy that showed a centrilobular necroinflammatory injury pattern suggest of early AIH without cirrhosis. The patient was started on oral budesonide followed by ofatumumab, an anti-CD20 monoclonal antibody approved for treatment of RRMS, as steroids were weaned. The patient’s liver enzymes returned to normal ranges within 12 weeks and have remained so now for approximately 8 months. Additionally, she has had no new clinical or imaging findings suggestive of MS disease activity. We present this as the first-reported case of the use of an anti-CD20 monoclonal antibody to treat both MS and AIH concurrently. Discussion: This case furthers our understanding of AIH by suggesting that the pathophysiology contributing to AIH is predominately B-cell related as this patient’s AIH was successfully treated with ofatumumab and a short course of budesonide. It highlights a possible alternative treatment modality for AIH that avoids a prolonged course of steroids and/or azathioprine. More research is still needed however.

S3191 TNF Inhibitor-Induced Liver Injury: Clinical Presentations and Outcomes

Introduction: Inflammatory bowel disease (IBD) is commonly treated with a sub-set of medications that inhibit tumor necrosis factor (TNF), an integral component during the pro-inflammatory phase. However, like all medications, TNF inhibitors are not without adverse side effects, one of them being drug induced liver injury (DILI). Although commonly described in literature, clinical presentation is often not encountered or recognized. We describe the cases of two individuals with IBD and the development of DILI secondary to TNF inhibition. Case Description/Methods: Our first case describes a 40-year-old female with ulcerative colitis who was started on adalimumab. Within 8 months of starting, aminotransferases were found to be elevated. Abdominal ultrasound showed hepatic steatosis, Fibroscan CAP 100, E Score 12kPa, and liver biopsy was consistent with autoimmune pattern liver injury with focal periportal fibrosis. Her only symptom was constipation. Adalimumab was discontinued and a short course of prednisone was started with improvement in aminotransferase elevations. Our second case is a 25-year-old female with Crohn’s Disease who was started on infliximab. Within 6 months, aminotransferases were found to be elevated. Liver biopsy showed portal-based chronic hepatitis with mild activity suspicious for DILI. Autoimmune hepatitis workup including ANA (640), A-SMA (negative), AMA (negative), Anti-dsDNA (60-borderline), IgG (1713) was not convincing but autoimmune hepatitis due to anti-TNF activity could not be excluded. At this time, infliximab was discontinued, and the patient began to have an improvement in clinical presentation. Discussion: All the TNF inhibitors currently marketed have been associated with DILI. However, the optimal management of liver injury related to TNF inhibitors is still a matter of debate. Some practitioners recommend the discontinuation of treatment in the case of elevated aminotransferase levels or the occurrence of jaundice. Others have recommended the continuation TNF inhibitor in the setting of similar clinical and laboratory findings with hopeful resolution of liver injury. Too often, the clinical signs or evidence of DILI is occult and can go unnoticed. Further research into best practice outcomes when IBD patients are taking such medications is needed. Additionally, better guidelines for the use and management of TNF inhibitors in IBD patients is imperative to minimize the risk of unchecked drug induced liver injury.

ZVAD alleviates experimental autoimmune hepatitis in mice by increasing the sensitivity of macrophage to TNFR1-dependent necroptosis

Background & aimsAutoimmune hepatitis (AIH) is characterized by hepatocyte destruction, leading to lymphocyte and macrophage accumulation in the liver. Macrophages are key drivers of AIH. A membrane-permeable pan-caspase inhibitor, Z-Val-Ala-DL-Asp-fluoromethylketone (zVAD), induces macrophage necroptosis in response to certain stimuli. However, the function of zVAD in the pathogenesis of autoimmune hepatitis remains elusive. In this study, we aimed to evaluate the effect and explore the underlying mechanisms of zVAD against AIH. MethodsMurine acute autoimmune liver injury was established by concanavalin A (ConA) injection. Bone marrow-derived macrophages (BMDMs) were used in adoptive cell transfer experiments. The mechanism of action of zVAD was examined using macrophage cell lines and BMDMs. Phosphorylation of mixed lineage kinase domain-like proteins was used as a marker of necroptosis. ResultsTreatment with zVAD increased necroptosis, reduced inflammatory cytokine production, and alleviated liver injury in a ConA-induced liver injury mouse model. Regardless of zVAD treatment, macrophage deletion resulted in reduced neutrophil accumulation and relieved ConA-induced liver injury. In vitro studies have shown that zVAD pretreatment promotes lipopolysaccharide-induced macrophage necroptosis and leads to reduced pro-inflammatory cytokine and chemokine secretion. Transferring zVAD-pretreated BMDMs in mice notably reduced ConA-associated liver inflammation and injury, resulting in lower mortality than that observed after transferring normal BMDMs. Mechanistically, zVAD treatment increased the expression of tumour necrosis factor receptor (TNFR)-1 and interleukin (IL)-10 in macrophages. TNFR1 expression decreased upon transfection with IL-10-specific small interfering RNAs and blocking of TNFR1 decreased macrophage necroptosis. ConclusionsWe found that zVAD alleviated ConA-induced liver injury by increasing the sensitivity of macrophages to necroptosis via IL-10-induced TNFR1 expression. This study provides new insights into the treatment of autoimmune hepatitis via zVAD-induced macrophage necroptosis.

Therapeutic effects of dexamethasone-loaded hyaluronan nanogels in the experimental cholestasis

A major function of the intrahepatic biliary epithelium is bicarbonate excretion in bile. Recent reports indicate that budesonide, a corticosteroid with high receptor affinity and hepatic first pass clearance, increases the efficacy of ursodeoxycholic acid, a choleretic agent, in primary biliary cholangitis patients. We have previously reported that bile ducts isolated from rats treated with dexamethasone or budesonide showed an enhanced activity of the Na+/H+ exchanger isoform 1 (NHE1) and Cl−/HCO3− exchanger protein 2 (AE2) . Increasing the delivery of steroids to the liver may result in three beneficial effects: increase in the choleresis, treatment of the autoimmune or inflammatory liver injury and reduction of steroids’ systemic harmful effects. In this study, the steroid dexamethasone was loaded into nanohydrogels (or nanogels, NHs), in order to investigate corticosteroid-induced increased activities of transport processes driving bicarbonate excretion in the biliary epithelium (NHE-1 isoform) and to evaluate the effects of dexamethasone-loaded NHs (NHs/dex) on liver injury induced by experimental cholestatis. Our results showed that NHs and NHs/dex do not reduce cell viability in vitro in human cholangiocyte cell lines. Primary and immortalized human cholangiocytes treated with NHs/dex show an increase in the functional marker expression of NHE1 cholangiocytes compared to control groups. A mouse model of cholangiopathy treated with NHs/dex shows a reduction in markers of hepatocellular injury compared to control groups (NHs, dex, or sham group). In conclusion, we believe that the NHs/dex formulation is a suitable candidate to be investigated in preclinical models of cholangiopathies.Graphical abstract

C/EBPα/miR-7 Controls CD4+ T-Cell Activation and Function and Orchestrates Experimental Autoimmune Hepatitis in Mice.

Increasing evidence in recent years has suggested that microRNA-7 (miR-7) is an important gene implicated in the development of various diseases including HCC. However, the role of miR-7 in autoimmune hepatitis (AIH) is unknown. Herein, we showed that miR-7 deficiency led to exacerbated pathology in Concanavalin-A-induced murine acute autoimmune liver injury (ALI) model, accompanied by hyperactivation state of CD4+ T cells. Depletion of CD4+ T cells reduced the effect of miR-7 deficiency on the pathology of ALI. Interestingly, miR-7 deficiency elevated CD4+ T-cell activation, proliferation, and cytokine production in vitro. Adoptive cell transfer experiments showed that miR-7def CD4+ T cells could exacerbate the pathology of ALI. Further analysis showed that miR-7 expression was up-regulated in activated CD4+ T cells. Importantly, the transcription of pre-miR-7b, a major resource of mature miR-7 in CD4+ T cells, was dominantly dependent on transcription factor CCAAT enhancer binding protein alpha (C/EBPα), which binds to the core promoter region of the miR-7b gene. Global gene analysis showed that mitogen-activated protein kinase 4 (MAPK4) is a target of miR-7 in CD4+ T cells. Finally, the loss of MAPK4 could ameliorate the activation state of CD4+ T cells with or without miR-7 deficiency. Our studies document the important role of miR-7 in the setting of AIH induced by Concanavalin-A. Specifically, we provide evidence that the C/EBPα/miR-7 axis negatively controls CD4+ T-cell activation and function through MAPK4, thereby orchestrating experimental AIH in mice. This study expands on the important role of miR-7 in liver-related diseases and reveals the value of the C/EBPα/miR-7 axis in CD4+ T-cell biological function for the pathogenesis of immune-mediated liver diseases.

Efficacy of rituximab in difficult-to-manage autoimmune hepatitis: Results from the International Autoimmune Hepatitis Group.

Background & AimsTreatment options remain limited for patients with autoimmune hepatitis (AIH), while there are still concerns over the consequences of long-term corticosteroid use. A few studies have suggested a role for B cell-driven autoimmune liver injury in AIH. This multicentre, international retrospective cohort study from the International Autoimmune Hepatitis Group aims to evaluate the clinical efficacy and safety of rituximab in difficult-to-manage AIH.MethodsClinical data from 22 patients who received rituximab between 2007 and 2017 were collected from centres in the United Kingdom, Germany and Canada. Clinical response was assessed using changes in biochemical and immunological parameters up to 24 months post-rituximab infusion. In addition, we compared the doses of prednisolone used 3 months before and 12 months after treatment, and assessed freedom from AIH flares over the post-treatment period.ResultsTwenty-two patients with type-1 AIH were included, with a median age of 40 years at diagnosis (range 19–79); 15/22 (68%) were female and 18/22 (82%) were Caucasian. The median period from diagnosis to the end of follow-up in these patients was 11 years (range 3–28). Values of alanine aminotransferase, aspartate aminotransferase and albumin improved significantly following rituximab therapy, and were sustained for up to 2 years (all p ≪0.001). Prednisolone doses were significantly reduced by 12 months post-treatment (p = 0.003), with 13/21 (62%) patients having a dose reduction. Over a median post-treatment follow-up period of 6 years (range 1–10), 5 patients developed AIH flares at a median of 22 months post-treatment, giving an estimated 71% freedom from AIH flare at 2 years. Four of these patients received a second course of treatment, of whom 2 had subsequent further flares. No serious adverse events attributable to rituximab were recorded.ConclusionIn patients with difficult-to-manage AIH, rituximab appears to be clinically effective and well tolerated. Rituximab was associated with sustained improvements in serum liver tests, an absence of clinical disease flares, and a reduction in prednisolone dose. Controlled trials are warranted to further evaluate B cell-targeting therapies in patients with AIH.Lay summaryAutoimmune hepatitis is an autoimmune condition of the liver, usually treated with medications that suppress the immune system, such as steroids. However, some patients do not respond to this treatment. We analysed the safety and efficacy of rituximab in patients who were not responding to first- or second-line therapies. Rituximab was safe and improved liver blood tests in 70% of patients over a 2-year follow-up period, while enabling steroid doses to be reduced in two-thirds of patients, which is a very positive clinical outcome.

Diammonium Glycyrrhizinate Mitigates Liver Injury Via Inhibiting Proliferation Of NKT Cells And Promoting Proliferation Of Tregs.

PurposeDiammonium glycyrrhizinate (DG) is a replacement for glycyrrhizic acid, which is used as a hepatic protector in clinical practice for most liver diseases. The potential role of immune response during autoimmune hepatitis—induced by concanavalin A (Con A)—remains to be elucidated.MethodsC57BL/6J mice were treated with two different doses of DG (75 and 200 mg/kg) 2 hrs before administering Con A. The mice were sacrificed after administering Con A for 0, 6, and 24 hrs. Liver damage grade and serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin levels were evaluated. The expression level of cleaved-caspase 3 in liver was detected by Western blotting. Inflammatory cytokines such as tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and interferon γ (IFN-γ) in liver were detected by RT-PCR. Thymus, peripheral blood, spleen, and liver tissues were collected to analyze the percentages of NKT cells, subsets of CD4+CD25−CD69+ and CD8+CD69+ T cells, and subsets of regulatory T cells (Tregs).ResultsOur results revealed that DG pre-treatment significantly decreased the serum ALT and AST levels and improved the histological damage in Con A-induced autoimmune liver injury. Pre-treatment with DG down-regulated the inflammatory cytokines upon challenge with Con A. The DG pre-treatment inhibited the apoptosis of T lymphocytes in the thymus. Further, it effectively suppressed the proliferation of CD4+CD25−CD69+ and CD8+CD69+ subsets in the peripheral blood and spleen. In addition, the DG pretreatment significantly downregulated the frequency of NKT cells, while upregulating the frequency of Tregs in the liver.ConclusionWe believe that the potential protective effect of DG against Con A-induced hepatitis may be partially attributed to its inhibitory activities on inflammatory cytokines in the livers, lymphocyte apoptosis in the thymus, NKT cells proliferation, and activation of CD8+T cells; further, there may also be a possibility of DC promoting Tregs proliferation.

Effect of trichloroacetaldehyde on the activation of CD4+T cells in occupational medicamentosa-like dermatitis: An in vivo and in vitro study

Occupational medicamentosa-like dermatitis induced by trichloroethylene (OMLDT) is a hypersensitivity disease with autoimmune liver injury, which has increasingly become a serious occupational health problem in China. However, the pathogenesis of OMLDT remained undefined. In this study, 30 TCE-induced OMLDT patients, 58 exposure controls, and 40 non-exposure controls were recruited. We showed that the ratio of activated CD4+ T cells (downregulation of CD62 L) was dramatically increased in OMLDT patients compared to exposure and non-exposure control, suggesting that CD4+ T cells activation was a key cellular event in the development of OMLDT. In parallel, the expression of cytokine including IL-2, IFN-γ, TNF-α and IL-17A were increased obviously and IL-4 decreased in CD4+ T cells from OMLDT patients. in vitro assay, we found that trichloroethylene metabolites trichloroacetaldehyde (TCAH), not trichloroacetic acid (TCA) or Trichloroethanol (TCOH) could activate the naïve CD4+ T cells characterized by a rise in intracellular calcium, down-regulated CD62 L and subsequently trigger the secretion of IL-2, IFN-γ and TNF-α. Notably, the phosphorylation status of NF-κB and p38MAPK were elevated in OMLDT patients. Moreover, TCAH also could activate the p38MAPK and NF-κB, suggesting the role of p38MAPK and NF-κB pathways in the activation of CD4+ T cells. In addition, we found that the inhibition of Schiff base formation decreased the ability of TCAH to induce the activation of naïve CD4+ T cells and p38MAPK and NF-κB pathway. In conclusion, we revealed that the CD4+ T activation and increased the cytokines including IL-2, IFN-γ and TNF-α but decreased IL-4 in CD4+ T cells were associated with OMLDT. TCAH could activate naïve CD4+ T cells through NF-κB and p38MAPK activation induced by Schiff base formation, which might contribute to the development of OMLDT. These findings provide a new insight into the pathogenesis of OMLDT.

Effects of TNFα signaling on iNKT cell development, activation and maturation

Abstract iNKT cells are CD1d-restricted T cells that recognize lipid antigens. Upon activation these cells rapidly produce large amount and a broad spectrum of cytokines. They are important immunoregulatory cells involved in autoimmune disease, liver injury and antitumor immunity. The mechanisms regarding iNKT cell development, activation and maturation have been studied extensively. It is well known that many cytokines and transcription factors are involved in these processes. TNFα, an inflammatory cytokine that can be produced by iNKT cells, co-occurs with iNKT cells in steady state and many disease conditions. How TNFα affects iNKT cell development, activation and maturation is not known. Herein we used a TNFα KO mouse model to address this issue. We found that depletion of TNFα did not affect the frequency of iNKT cells in thymus and spleen, but decreased iNKT cells in liver, and increased iNKT cell apoptosis in liver. The portion of stage-2 (NK1.1loCD44hi) iNKT cells increased, stage-3 (NK1.1hiCD44hi) iNKT cells decreased in the thymus of TNFα KO mice, suggesting that depletion of TNFα impairs iNKT cell development and maturation. The percentage of CD69+ iNKT cells was significantly lower in the thymus, spleen and liver of TNFα KO mice compared to their wild-type littermates, suggesting that depletion of TNFα inhibits iNKT cell activation. Moreover, upon activation, the percentage of splenic IL-4- and IFN-g-producing iNKT cells was significantly lower in TNFα KO mice than in their wild-type littermates. Depletion of TNFα increased PLZF+ iNKT cells in thymus and downregulated the expression of CD122 on iNKT cells. Taken together, TNFα signaling plays important roles in regulation of iNKT cell development, activation and maturation.

The Antidepressant Mirtazapine Inhibits Hepatic Innate Immune Networks to Attenuate Immune-Mediated Liver Injury in Mice.

Activation of the innate immune system, including tissue macrophages and associated neutrophil infiltration, is an important driver of subsequent adaptive immune responses in many autoimmune diseases, including autoimmune hepatitis (AIH). The antidepressant mirtazapine has a unique complex pharmacology, altering signaling through a number of serotonin and histamine receptors that can impact macrophage function; an effect potentially influencing AIH outcome. In the mouse model of concanavalin A (Con A) induced liver injury (mimics many aspects of human AIH), in which early innate immune activation (i.e., stimulated hepatic macrophages/monocytes recruit neutrophils and additional monocytes to the liver) critically drives immune-mediated hepatitis induction, mirtazapine strikingly and dose-dependently inhibited Con A-induced liver injury. This inflammation-suppressing effect of mirtazapine was linked to an attenuation of Con A-stimulated early innate immune responses within the liver, including inhibition of hepatic macrophage/monocyte activation, decreased hepatic macrophage/monocyte-derived pro-inflammatory cytokine (e.g., TNFα) and chemokine (e.g., CXCL1 and CXCL2) production, suppression of Con A-induced increases in the hepatic expression of the neutrophil relevant endothelial cell adhesion molecule ICAM-1, with the resultant significant reduction in neutrophil recruitment into the liver. Consistent with our findings in the Con A model, mirtazapine also significantly reduced activation-induced release of cytokine/chemokine mediators from human CD14+ monocytes in vitro.Conclusion: Our data suggest that mirtazapine can attenuate hepatic innate immune responses that critically regulate the subsequent development of autoimmune liver injury. Therefore, given that it is a safe and widely used medication, mirtazapine may represent a novel therapeutic approach to autoimmune liver disease.

Hepatotoxicity of Inflammatory Bowel Disease Medications.

Various medications used to treat inflammatory bowel diseases have been implicated to cause hepatotoxicity. These include sulfasalazine, 5-aminosalicylic acids, fluoroquinolones, metronidazole, thiopurines, methotrexate, anti-tumor necrosis factor agents, and alpha-4 integrin inhibitors. Various types of liver injury have been reported in association with these medications including hypersensitivity reaction, hepatocellular or cholestatic disease, nodular regenerative hyperplasia, liver fibrosis/cirrhosis, portal hypertension and autoimmune liver injury. The revised Roussel Uclaf Causality Assessment Method (RUCAM) provides a scoring system to determine the likelihood of whether a drug caused liver injury. Unfortunately some of the reported liver injuries in association with these treatments have not undergone RUCAM assessment. Therefore, although some of the reports used in this review article show an association between a medication and the reported liver injury, they may not necessarily show causation. In this article, we address methods of monitoring to detect these injuries. We also discuss the prognosis and recommended management plans when liver injury occurs.

Protective effects of artesunate against Con A-induced autoimmune liver injury in mice

Autoimmune liver disease is a refractory disease clinically, and there is no particularly effective drug at present. Therefore, it is of important clinical value to develop new effective intervention drugs for the prevention and treatment of autoimmune liver disease. In order to investigate the potential protective effect of artesunate (Art) on concanavalin A (Con A)-induced autoimmune liver injury, different doses of Art (27, 54, 108 mg·kg⁻¹) were orally administered to mice for consecutive 7 days, respectively. Then the Con A was injected into mice via tail vein to induce liver injury models. 8 h after modeling, the mice were sacrificed. The serum and liver tissue were collected for detecting the level of alanine aminotransferase (ALT), and aspartate transaminase (AST), liver pathological histopathology, inflammatory cytokines and nuclear factor (NF-κB) key protein expression level. The results showed that 108 mg·kg⁻¹ Art remarkably reduced Con A-induced liver indexes and serum transaminase levels (ALT and AST) as compared with model group(P<0.01). Meanwhile, the liver histopathological changes were obviously alleviated with a significant decrease of pro-inflammatory cytokine including tumor necrosis factor (TNF-α), interferon (IFN-γ), interleukin (IL-6), IL-17 and a higher increase of anti-inflammatory cytokine IL-10 (P<0.01). Western blot results showed that 108 mg·kg⁻¹ Art markedly inhibited the expressions of p-p65 and p-IκBα proteins (P<0.01). The specific inhibitor of NF-κB, pyrrolidinedithiocarbamate (PDTC) could also significantly inhibit the expressions of p-p65 and p-IκBα with and alleviate liver injuries. Therefore, our results indicated that Art may have a protective action against Con A-induced autoimmune liver injury mainly by suppressing NF-κB signal pathway in mice. The study provides scientific reference for artesunate usage in preventing autoimmune liver injury.

Protective effects of Punica granatum (pomegranate) peel extract on concanavalin A-induced autoimmune hepatitis in mice

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease of an unknown etiology, glucocorticoid therapy is currently recognized as an effective treatment for AIH, but conventional application and patient compliance are both hindered by its side effects. The exploration of the AIH pathogenesis and the searching for the new candidate drugs that exert potential activity and low toxicity are urgently needed. Pomegranate peel extract (PoPx) is a natural extract of Punica granatum and has been reported to have anti-inflammatory and antioxidative properties. The present study aimed to clarify the effect of PoPx on the concanavalin A (ConA)-induced autoimmune hepatitis in a mouse model that is well established at 12h after tail vein injection with a dose of 20 mg/kg of ConA. C57BL/6 female mice were pretreated with PoPx (250 mg/kg, once daily for 3 days) followed by a ConA challenge. Pretreatment with PoPx significantly alleviated ConA-induced liver injury by down-regulating the levels of plasma alanine transaminase (ALT), aspartate transaminase (AST) and cytokine, including TNF-α, interferon (IFN) -γ and interleukin (IL)-6. Moreover, liver hematoxylin and eosin (H&E) staining displayed a lighter inflammatory infiltration around the portal area in the PoPx-pretreated mice. In addition, the flow cytometry (FCM) data showed that the immune response in the liver was died down in the PoPx-pretreated condition. Specially, pretreatment with PoPx reduced the infiltration of activated CD4+ and CD8+ T cells in the liver. Taken together, these findings contributed to a better understanding of the actions of PoPx against acute AIH and indicated that PoPx might be a potential compound in treating T cell-mediated autoimmune liver injury.

Diclofenac-Induced Post Infantile Giant Cell Hepatitis

INTRODUCTION: Post-infantile Giant Cell Hepatitis (PIGCH) is a rare type of autoimmune hepatitis (AIH) characterized by an idiosyncratic response to liver injury from various causes in which liver cells respond to insult by rapid proliferation and without the appropriate cellular division, leading to the formation of the multi-nucleated giant cells. We encountered a case of Diclofenac induced PIGCH in a patient with untreated seropositive rheumatoid arthritis. To the best of our knowledge, this is first such case reported in the literature. CASE PRESENTATION: A 48-year-old Hispanic woman with type II diabetes and rheumatoid arthritis, not on DMARDs presented with acute onset jaundice and right upper quadrant pain. She was taking 50mg of Diclofenac, 2 pills daily for the past 3 months and unknown quantity of garlic tablets. Workup for hepatitis including infectious and toxic etiologies were ruled out. Serum IgG levels were elevated with increased globuin gap, and positive ANA titer of 640, anti-smooth muscle cell antibodies elevated at 41 units (moderate to strong positive > 30 units). Liver biopsy demonstrated submassive necrosis in the setting of post-infantile giant cell hepatitis. The differential diagnoses included idiopathic autoimmune hepatitis, viral or drug induced injury. Our diagnosis was drug induced autoimmune liver disease (DIALD), the etiology is likely due to Diclofenac given temporal relationship of drug intake and symptom onset, as well as a calculated Roussel Uclaf Causality Assessment Method (RUCAM) score of 6, signifying probable drug-induced liver disease. Patient was started on Prednisone and Azathioprine with complete resolution of clinical and laboratory findings within 5 months. DISCUSSION: The outcome of PIGCH is unpredictable, usually adopts a fulminant course leading to cirrhosis within months, however, a more benign course has also been described. PIGCH is triggered by three primary etiologies: drugs, infection, and autoimmune liver injury. This case highlights that giant cell hepatitis is a multifactorial condition that can be precipitated by drug use in the setting of autoimmune phenotype. Garlic and garlic extracts, through their antioxidant activities, have been reported to provide protection against free radical damage in the body. The innocuous course of PIGCH in our patient could possibly be due to concurrent consumption of garlic tablets. Further research is needed in this area.

The good and the bad collagens of fibrosis - Their role in signaling and organ function.

Usually the dense extracellular structure in fibrotic tissues is described as extracellular matrix (ECM) or simply as collagen. However, fibrosis is not just fibrosis, which is already exemplified by the variant morphological characteristics of fibrosis due to viral versus cholestatic, autoimmune or toxic liver injury, with reticular, chicken wire and bridging fibrosis. Importantly, the overall composition of the ECM, especially the relative amounts of the many types of collagens, which represent the most abundant ECM molecules and which centrally modulate cellular functions and physiological processes, changes dramatically during fibrosis progression. We hypothesize that there are good and bad collagens in fibrosis and that a change of location alone may change the function from good to bad. Whereas basement membrane collagen type IV anchors epithelial and other cells in a polarized manner, the interstitial fibroblast collagens type I and III do not provide directional information. In addition, feedback loops from biologically active degradation products of some collagens are examples of the importance of having the right collagen at the right place and at the right time controlling cell function, proliferation, matrix production and fate. Examples are the interstitial collagen type VI and basement membrane collagen type XVIII. Their carboxyterminal propeptides serve as an adipose tissue hormone, endotrophin, and as a regulator of angiogenesis, endostatin, respectively. We provide an overview of the 28 known collagen types and propose that the molecular composition of the ECM in fibrosis needs careful attention to assess its impact on organ function and its potential to progress or reverse. Consequently, to adequately assess fibrosis and to design optimal antifibrotic therapies, we need to dissect the molecular entity of fibrosis for the molecular composition and spatial distribution of collagens and the associated ECM.

Cellular and Molecular Mechanisms of Autoimmune Hepatitis.

Autoimmune hepatitis is an uncommon idiopathic syndrome of immune-mediated destruction of hepatocytes, typically associated with autoantibodies. The disease etiology is incompletely understood but includes a clear association with human leukocyte antigen (HLA) variants and other non-HLA gene variants, female sex, and the environment. Pathologically, there is a CD4+ T cell-rich lymphocytic inflammatory infiltrate with variable hepatocyte necrosis and subsequent hepatic fibrosis. Attempts to understand pathogenesis are informed by several monogenetic syndromes that may include autoimmune liver injury, by several drug and environmental agents that have been identified as triggers in a minority of cases, by human studies that point toward a central role for CD4+ effector and regulatory T cells, and by animal models of the disease. Nonspecific immunosuppression is the current standard therapy. Further understanding of the disease's cellular and molecular mechanisms may assist in the design of better-targeted therapies, aid the limitation of adverse effects from therapy, and inform individualized risk assessment and prognostication.

Trichloroethylene Exposure Reduces Liver Injury in a Mouse Model of Primary Biliary Cholangitis.

Trichloroethylene (TCE) is a persistent environmental contaminant proposed to contribute to autoimmune disease. Experimental studies in lupus-prone MRL+/+ mice have suggested that TCE exposure can trigger autoimmune hepatitis. The vast majority of studies examining the connection between TCE and autoimmunity utilize this model, and the impact of TCE exposure in other established models of autoimmune liver disease is not known. We tested the hypothesis that TCE exposure exacerbates experimental hepatic autoimmunity in dominant negative transforming growth factor beta receptor type II (dnTGFBRII) mice, which develop serological and histological features resembling human primary biliary cholangitis. Female 8-week-old wild-type and dnTGFBRII mice were exposed to TCE (0.5 mg/ml) or vehicle (1% ethoxylated castor oil) in the drinking water for 12 or 22 weeks. Liver histopathology in 20- and 30-week-old wild-type mice was unremarkable irrespective of treatment. Mild portal inflammation was observed in vehicle-exposed 20-week-old dnTGFBRII mice and was not exacerbated by TCE exposure. Vehicle-exposed 30-week-old dnTGFBRII mice developed anti-mitochondrial antibodies, marked hepatic inflammation with necrosis, and hepatic accumulation of both B and T lymphocytes. To our surprise, TCE exposure dramatically reduced hepatic parenchymal inflammation and injury in 30-week-old dnTGFBRII mice, reflected by changes in hepatic proinflammatory gene expression, serum chemistry, and histopathology. Interestingly, TCE did not affect hepatic B cell accumulation or induction of the anti-inflammatory cytokine IL10. These data indicate that TCE exposure reduces autoimmune liver injury in female dnTGFBRII mice and suggests that the precise effect of environmental chemicals in autoimmunity depends on the experimental model.