Cirrhotic patients with minimal hepatic encephalopathy have increased capacity to eliminate superoxide and peroxynitrite in lymphocytes, associated with cognitive impairment

Sex is associated with differences in oxidative stress and susceptibility to severe hepatic encephalopathy in bile-duct ligated rats

Hepatic encephalopathy (HE) is a debilitating neurological complication of chronic liver disease (CLD). Hyperammonemia plays an important role in HE's pathogenesis, acting synergistically with systemic oxidative stress. During CLD, muscle plays a compensatory role in detoxifying ammonia, and therefore muscle loss leads to an increase in the risk of developing HE. With most animal studies involving males, sex's impact on the development of CLD and associated complications such as HE and muscle loss remains unknown. Therefore, we aimed to identify the impact of sex on CLD, HE, and muscle mass loss in a rodent model of CLD. Liver injury markers, hyperammonemia, oxidative stress, muscle mass and ammonia clearance were measured in female and male bile-duct ligated (BDL) rats. In addition, covert HE was assessed in females while ammonia-precipitated severe HE was assessed in female and male BDL rats, and male BDL rats treated with allopurinol (100mg/kg), an antioxidant (xanthine oxidase inhibitor). Female BDL developed CLD and HE (impaired motor-coordination and night activity) compared to respective SHAM. Hyperammonemia and muscle ammonia clearance were similar between female and male BDL. However, only female BDL rats did not develop muscle loss, brain edema, and short-term memory impairment (vs. female SHAM) and systemic oxidative stress and decreased albumin levels (vs. male BDL). Furthermore, both female BDL and allopurinol-treated male BDL rats were protected against ammonia-induced overt HE. In conclusion, female and male BDL rats develop distinct features of CLD and HE, with systemic oxidative stress playing a pivotal role in the susceptibility to ammonia precipitated overt HE.

Rifaximin Improves Spatial Learning and Memory Impairment in Rats with Liver Damage-Associated Neuroinflammation

Patients with non-alcoholic fatty liver disease (NAFLD) may show mild cognitive impairment. Neuroinflammation in the hippocampus mediates cognitive impairment in rat models of minimal hepatic encephalopathy (MHE). Treatment with rifaximin reverses cognitive impairment in a large proportion of cirrhotic patients with MHE. However, the underlying mechanisms remain unclear. The aims of this work were to assess if rats with mild liver damage, as a model of NAFLD, show neuroinflammation in the hippocampus and impaired cognitive function, if treatment with rifaximin reverses it, and to study the underlying mechanisms. Mild liver damage was induced with carbon-tetrachloride. Infiltration of immune cells, glial activation, and cytokine expression, as well as glutamate receptors expression in the hippocampus and cognitive function were assessed. We assessed the effects of daily treatment with rifaximin on the alterations showed by these rats. Rats with mild liver damage showed hippocampal neuroinflammation, reduced membrane expression of glutamate N-methyl-D-aspartate (NMDA) receptor subunits, and impaired spatial memory. Increased C-C Motif Chemokine Ligand 2 (CCL2), infiltration of monocytes, microglia activation, and increased tumor necrosis factor α (TNFα) were reversed by rifaximin, that normalized NMDA receptor expression and improved spatial memory. Thus, rifaximin reduces neuroinflammation and improves cognitive function in rats with mild liver damage, being a promising therapy for patients with NAFLD showing mild cognitive impairment.

Effect of plumbagin on autophagy activity in rat hepatocellular carcinoma and underlying mechanism

BACKGROUND

Autophagy is a multi-step lysosomal degradation pathway supporting nutritional cycle and metabolic adaptation, which is considered to be a process of regulating cancer progression. In this study, rats with hepatocellular carcinoma (HCC) were treated with plumbagin to explore its effect on the autophagy activityin HCC, in order to provide a new idea for the treatment of this malignancy.

AIM

To investigate the effect of plumbagin on autophagy activity in aflatoxin B1 (AFB1)-induced rat hepatocellular carcinoma and to explore the possible mechanism involved.

METHODS

AFB1 was used to develop a rat hepatocellular carcinoma model. The rats were then treated with plumbagin. The ultrastructure of liver tissues and autophagic cells was observed by electron microscopy. The expression of AKT1 mRNA and protein was measured by RT-PCR and immunohistochemical staining, respectively. Western blot was used to detect the expression of LC3B Ⅰ and LC3B Ⅱ protein in liver tissue.

RESULTS

Autophagy was common in liver tissues of the AFB1-induced cancer model group and plumbagin treated group. Compared with the control group, the expression levels of AKT1 mRNA and protein in the liver tissues of the AFB1-induced cancer model group were significantly increased (t = 17.013 and 9.986, respectively, P < 0.001).The expression of AKT1 mRNA in liver tissue of rats treated with 2 mg/kg and 3 mg/kg plumbagin was significantly lower than that of the AFB1-induced cancer model group (t = -2.378, P = 0.030; t = -17.980, P < 0.001). Compsared with the AFB1-induced cancer model group, the LC3B-II/I ratio in the liver tissue of rats treated with 2 mg/kg and 3 mg/kg plumbagin was significantly increased (t = 2.420, P = 0.028; t = 35.136, P < 0.001). The LC3B-II/I ratio in rat liver tissue was significantly different between the 2 mg/kg and 3 mg/kg plumbagin treatment groups (t = 21.316, P < 0.001). There was a significant correlation between the expression of AKT1 mRNA and the LC3B-II/I ratio in the liver tissue of rats treated with 3 mg/kg plumbagin (r = -0.611, P = 0.035).

CONCLUSION

Plumbagin may enhance the autophagy activity of rat HCC cells by inhibiting the expression of ATK1.