Protective effect of FTY720 on several markers of liver injury induced by concanavalin a in mice

Research progress on rodent models and its mechanisms of liver injury

The liver is the most important organ for biological transformation in the body and is crucial for maintaining the body's vital activities. Liver injury is a serious pathological condition that is commonly found in many liver diseases. It has a high incidence rate, is difficult to cure, and is prone to recurrence. Liver injury can cause serious harm to the body, ranging from mild to severe fatty liver disease. If the condition continues to worsen, it can lead to liver fibrosis and cirrhosis, ultimately resulting in liver failure or liver cancer, which can seriously endanger human life and health. Therefore, establishing an rodent model that mimics the pathogenesis and severity of clinical liver injury is of great significance for better understanding the pathogenesis of liver injury patients and developing more effective clinical treatment methods. The author of this article summarizes common chemical liver injury models, immune liver injury models, alcoholic liver injury models, drug-induced liver injury models, and systematically elaborates on the modeling methods, mechanisms of action, pathways of action, and advantages or disadvantages of each type of model. The aim of this study is to establish reliable rodent models for researchers to use in exploring anti-liver injury and hepatoprotective drugs. By creating more accurate theoretical frameworks, we hope to provide new insights into the treatment of clinical liver injury diseases.

Effects of fingolimod treatments on alanine transaminase and aspartate transaminase levels in patients with multiple sclerosis

INTRODUCTION

Multiple Sclerosis (MS) is a chronic neurological disorder with no known cause or cure. Fingolimod (FTY720) is an oral medication recently approved for the treatment of MS as well as other diseases with autoimmune aspects. However, the drug is not without side effects. The severity and prevalence of these side effects are not completely understood. One of the most common causes for the patient cessation of fingolimod is an increase in liver enzymes, indicating possible inflammation or damage to liver cells. Alanine transaminase (ALT) and aspartate transaminase (AST) are the most common liver enzymes used as indicators of hepatic health.

OBJECTIVES

This three-month prospective cohort study selected patients who were diagnosed with relapsing-remitting MS (RRMS) and who were not taking fingolimod oral treatment. ALT and AST levels were determined for these patients at baseline and then after three months of taking FTY720 to determine if these liver enzymes were changed.

METHODS

36 RRMS patients completed this study, which lasted three months. They were started on 0.5 oral FTY720 after approval from a physician and completion of an AST/ALT blood test. Baseline levels were determined and then taken again three months later. Statistical analysis of these values was performed using P<0.05 as a significance threshold.

RESULTS

In this sample of patients, only ALT levels were significantly increased after fingolimod treatment in the general cohort (P=0.00). The general cohort showed an insignificant increase in AST levels. In male and female populations separately, AST was not significantly increased. ALT was only significantly increased in men (P=0.00) and insignificantly increased in women.

CONCLUSION

This study further confirms our concerns about fingolimod's possible effects on the liver. While these numbers do support the claim that the drug does on average increase ALT in patient populations, it is important to note that most of these patients have no real hepatic side effects. In addition, previous studies have cited a return to normal ALT and AST levels after cessation of fingolimod, suggesting its effects are temporary and not severely damaged in the usual patient.

Genetic Loss of Immunoglobulin A Does Not Influence Development of Alcoholic Steatohepatitis in Mice

BACKGROUND

Chronic alcohol abuse is associated with intestinal dysbiosis and bacterial translocation. Translocated commensal bacteria contribute to alcoholic liver disease. Secretory immunoglobulin A (IgA) in the intestine binds bacteria and prevents bacterial translocation.

METHODS

To investigate the functional role of IgA in ethanol (EtOH)-induced liver disease in mice, we subjected wild type (WT) and IgA-deficient littermate mice to Lieber-DeCarli models of chronic EtOH administration and the model of chronic and binge EtOH feeding (the NIAAA model).

RESULTS

Chronic EtOH feeding increased systemic levels of IgA, while fecal IgA was reduced in C57BL/6 WT mice. WT and Iga^-/- littermate mice showed similar liver injury, steatosis, and inflammation following 4 weeks of EtOH feeding or chronic and binge EtOH feeding. IgA deficiency did not affect intestinal absorption or hepatic metabolism of EtOH. Pretreatment with ampicillin elevated intestinal IgA in WT littermate mice. Despite increased intestinal IgA, WT littermate mice exhibited a similar degree of liver disease compared with Iga^-/- mice after 7 weeks of EtOH feeding. Interestingly, bacterial translocation to mesenteric lymph nodes was increased in Iga^-/- mice fed an isocaloric diet, but was the same after EtOH feeding relative to WT littermate mice. The absence of intestinal IgA was associated with increased intestinal and plasma IgM in Iga^-/- mice after EtOH feeding.

CONCLUSIONS

Our findings indicate that absence of IgA does not affect the development of alcoholic liver disease in mice. Loss of intestinal IgA is compensated by increased levels of intestinal IgM, which likely limits bacterial translocation after chronic EtOH administration.

Mouse and Human Liver Contain Immunoglobulin A-Secreting Cells Originating From Peyer's Patches and Directed Against Intestinal Antigens

BACKGROUND & AIMS

The liver receives blood from the gastrointestinal tract through the portal vein, and thereby is exposed continuously to dietary antigens and commensal bacteria. Alcoholic liver disease (ALD) is associated with intestinal dysbiosis, increased intestinal permeability, release of microbes into the portal circulation, and increased serum levels and liver deposits of IgA. We characterized B-cell production of IgA in livers of mice at homeostasis, after oral immunization, in a mouse model of ALD and in human liver samples.

METHODS

We performed studies with Balb/c and C57BL/6-Ly5.1 mice, as well as transgenic mice (quasimonoclonal, activation-induced [cytidine] deaminase-Cre-tamoxifen-dependent estrogen receptor 2 [ERT2], Blimp-1-green fluorescent protein [GFP]). C57BL/6-Ly5.1 mice were fed chronic plus binge ethanol to create a model of ALD. Some mice also were given repeated injections of FTY720, which prevents egress of IgA-secreting cells from Peyer's patches. We obtained nontumor liver tissues from patients with colorectal carcinoma undergoing surgery for liver metastases or hepatocellular carcinoma. B cells were isolated from mouse and human liver tissues and analyzed by flow cytometry and enzyme-linked ImmunoSpot (ELISpot). In wild-type and transgenic mice, we traced newly generated IgA-secreting cells at steady state and after oral immunization with 4-hydroxy-3-nitrophenylacetyl (NP)-Ficoll or cholera toxin. IgA responses were also evaluated in our model of ALD.

RESULTS

Livers of control mice contained proliferative plasmablasts that originated from Peyer's patches and produced IgAs reactive to commensal bacteria. After oral immunization with cholera toxin or a thymus-independent antigen, a substantial number of antigen-specific IgA-secreting cells was found in the liver. Mice fed ethanol had features of hepatitis and increased numbers of IgA-secreting cells in liver, compared with mice given control diets, as well as higher levels of serum IgA and IgA deposits in liver sinusoids. Injection of FTY720 during ethanol feeding reduced liver and serum levels of IgA and IgA deposits in liver and prevented liver injury. Human liver tissues contained a significant proportion of IgA-producing plasma cells that shared phenotypic and functional attributes with those from mouse liver, including reactivity to commensal bacteria.

CONCLUSIONS

Based on studies of mice and human liver tissues, we found the liver to be a site of IgA production by B cells, derived from gut-associated lymphoid tissues. These IgAs react with commensal bacteria and oral antigens. Livers from mice with ethanol-induced injury contain increased numbers of IgA-secreting cells and have IgA deposits in sinusoids. IgAs in the liver could mediate clearance of gut-derived antigens that arrive through portal circulation at homeostasis and protect these organs from pathogens.