The anti-inflammatory effect of Pien Tze Huang in non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease that may progress to nonalcoholic steatohepatitis (NASH), hepatic tissue fibrosis, liver cirrhosis, and hepatocellular carcinoma. In this study, we investigated the effects of Pien Tze Huang (PTH), a well-known traditional Chinese herbal formula with liver protective effect, in methionine-choline deficient diet (MCD)- and high-fat diet (HFD)-induced NASH mouse models. Our results showed that PTH could exert hepatoprotective effects by improving liver weight and steatosis and reducing the fibrosis and serum levels of alanine transaminase (ALT) and aspartate transaminase (AST) in both animal models. The effects of PTH was accompanied with the reduction of infiltrated macrophages, the inhibition of the expression of cytokines, and the induction of adiponectin expression. Mechanistically, we found that PTH could inhibit the activation of proinflammatory transcription factor nuclear factor-κB (NF-κB) by preventing the degradation of inhibitor of κBα (IκBα). These results demonstrate that PTH can improve NAFLD largely due to its suppression of the NF-κB inflammatory pathway.

Baking of methionine-choline deficient diet aggravates testis injury in mice

Dietary pattern and cooking methods are important factors to determine the nutrients supplementation for male reproduction. Methionine and choline are two methyl donors in daily diet, which could mediate the lipid metabolism, but their effects on the sperms are not clear. In this study, we fed the mice with methionine-choline deficient (MCD) diet or the baked MCD diet for 6 weeks to evaluate this dietary pattern and the appended high temperature cooking on the spermatogenesis. The results have shown that MCD diet induced testis degradation and the damage of spermatocytes, reduced sperm vitality, motility, but elevated sperm deformity. Additionally, baking of MCD diet aggravated the testis injury, further reduced sperm density, sperm motility, and decreased normal sperm morphology dramatically. These changes were not related to the blood-testis barrier nor the Leydig cells dysfunction, but related to spermatocytes lost and apoptosis. The spermatocyte apoptosis was mediated by reticulum stress, including GRP78, XBP-1 and CHOP gene expression. Our study has shown the importance of methionine and choline in diet, and emphasized the crucial role of cooking condition, which are dietary factors to influence the quality of sperms.

Hepatoprotective effect of Qushihuayu formula on non-alcoholic steatohepatitis induced by MCD diet in rat

Background

Non-alcoholic steatohepatitis (NASH) is an advanced form of non-alcoholic fatty liver disease (NAFLD) for which there is yet any standard pharmacotherapy. Traditional Chinese medicine formula such as Qushihuayu (QSHY) composing of multiple bioactive compounds has been used to treat NAFLD and NASH and shows beneficial effects over single compound treatment. This study aimed to investigate the mechanism of hepatoprotective effect of QSHY formula using a rat model.

Methods

Six-weeks old male Wistar rats were given methionine/choline supplemented (MCS) diet for 8 weeks and used as the blank control. Another 7 rats, which received methionine/choline deficient (MCD) diet in the first 6 weeks and a MCS&MCD (1:1) mixture diet in the last 2 weeks, were used as the model group. The groups of QSHY pre-treatment, low dosage, medium dosage and high dosage were given the same diet as the model group. Except for pre-treatment group (1 week in advanced of other groups), all QSHY treatment groups received QSHY formula by gavage every day since the MCD diet started.

Results

In the MCD diet group, the QSHY formula decreased the serum ALT and AST levels, lipid droplets, inflammation foci, FAS and α-SMA protein expression than MCD diet group. MAPK pathways phospharylation were markedly depressed by the QSHY formula. Moreover, QSHY formula enhanced PPAR-γ and p-p65 translocating into nucleus. The administration of QSHY increased hepatic mRNA levels of Transcription Factor 1 alpha (HNF1A), Hepatocyte Nuclear Factor 4 alpha (HNF4A) and Forkhead box protein A3 (FOXA3) which play a pivotal role in Hepatic stellate cell (HSCs) reprogramming.

Conclusion

These findings suggest that QSHY formula exerts a hepatoprotective effect against steatosis and fibrosis presumably via depressed MAPK pathways phosphorylation, reinforcement of PPAR-γ and p-p65 translocating into nucleus and enhanced HSCs reprogramming.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00434-1.

The GLP-1R agonist liraglutide limits hepatic lipotoxicity and inflammatory response in mice fed a methionine-choline deficient diet

Nonalcoholic fatty liver disease (NAFLD) is the most common hepatic disorder related to type 2 diabetes (T2D). The disease can evolve toward nonalcoholic steatohepatitis (NASH), a state of hepatic inflammation and fibrosis. There is presently no drug that effectively improves and/or prevents NAFLD/NASH/fibrosis. GLP-1 receptor agonists (GLP-1Ra) are effective in treating T2D. As with the endogenous gut incretins, GLP-1Ra potentiate glucose-induced insulin secretion. In addition, GLP-1Ra limit food intake and weight gain, additional beneficial properties in the context of obesity/insulin-resistance. Nevertheless, these pleiotropic effects of GLP-1Ra complicate the elucidation of their direct action on the liver. In the present study, we used the classical methionine-choline deficient (MCD) dietary model to investigate the potential direct hepatic actions of the GLP-1Ra liraglutide. A 4-week infusion of liraglutide (570 µg/kg/day) did not impact body weight, fat accretion or glycemic control in MCD-diet fed mice, confirming the suitability of this model for avoiding confounding factors. Liraglutide treatment did not prevent lipid deposition in the liver of MCD-fed mice but limited the accumulation of C16 and C24-ceramide/sphingomyelin species. In addition, liraglutide treatment alleviated hepatic inflammation (in particular accumulation of M1 pro-inflammatory macrophages) and initiation of fibrosis. Liraglutide also influenced the composition of gut microbiota induced by the MCD-diet. This included recovery of a normal Bacteroides proportion and, among the Erysipelotrichaceae family, a shift between Allobaculum and Turicibacter genera. In conclusion, liraglutide prevents accumulation of C16 and C24-ceramides/sphingomyelins species, inflammation and initiation of fibrosis in MCD-diet-fed mice liver, suggesting beneficial hepatic actions independent of weight loss and global hepatic steatosis.

Hepatic metabolomics reveals that liver injury increases PCB 126-induced oxidative stress and metabolic dysfunction

The deleterious effects of PCB 126 are complex, and the role of the liver in modifying toxic insult is not well understood. We utilized metabolomics approaches to compare liver metabolites significantly affected by PCB 126 in control mice and a diet induced liver injury mouse model. In this 14-week study, mice were fed either an amino acid supplemented control diet (CD) or a methionine-choline deficient diet (MCD) which promoted nonalcoholic steatohepatitis (NASH) and were subsequently exposed to PCB 126. The liver metabolome was profiled by a global metabolomic analysis using LC-MS. There were clear differences between PCB 126 exposed and control mice in the hepatic metabolomic profiles (216 and 266 metabolites were altered in CD-fed and MCD-fed mice respectively after PCB 126 exposure). PCB 126 modulated glycerophospholipid metabolism, glutathione metabolism, and CoA biosynthesis pathways irrespective of diet; indicating that the disturbance in lipid metabolism and thiol metabolites are general markers of PCB 126 exposure irrespective of liver health. Additionally, metabolites associated with oxidative stress and mitochondrial dysfunction were greatly elevated in PCB 126 exposed mice with compromised livers (e.g., 4-hydroxy-nonenal glutathione, oxylipids, uric acid, and acylcarnitines). Moreover, PCB 126 exposure downregulated redox genes, and the effect was more pronounced in liver injury mice. In conclusion, this study demonstrates that PCB 126 could induce oxidative stress and metabolic dysfunction, and pre-existing liver injury can markedly modify PCB 126-induced metabolic changes. Using metabolic profiling, this study suggests mechanism of enhanced PCB 126 toxicity under liver injury settings.

Dynamic alterations in the gut microbiota and metabolome during the development of methionine-choline-deficient diet-induced nonalcoholic steatohepatitis

AIM

To investigate changes in gut microbiota and metabolism during nonalcoholic steatohepatitis (NASH) development in mice fed a methionine-choline-deficient (MCD) diet.

METHODS

Twenty-four male C57BL/6J mice were equally divided into four groups and fed a methionine-choline-sufficient diet for 2 wk (Control 2w group, n = 6) or 4 wk (Control 4w group, n = 6) or the MCD diet for 2 wk (MCD 2w group, n = 6) or 4 wk (MCD 4w group, n = 6). Liver injury, fibrosis, and intestinal barrier function were evaluated after 2 and 4 wk of feeding. The fecal microbiome and metabolome were studied using 16s rRNA deep sequencing and gas chromatography-mass spectrometry.

RESULTS

The mice fed the MCD diet presented with simple hepatic steatosis and slight intestinal barrier deterioration after 2 wk. After 4 wk of feeding with the MCD diet, however, the mice developed prominent NASH with liver fibrosis, and the intestinal barrier was more impaired. Compared with the control diet, the MCD diet induced gradual gut microbiota dysbiosis, as evidenced by a marked decrease in the abundance of Alistipes and the (Eubacterium) coprostanoligenes group (P < 0.001 and P < 0.05, respectively) and a significant increase in Ruminococcaceae UCG 014 abundance (P < 0.05) after 2 wk. At 4 wk, the MCD diet significantly reduced the promising probiotic Bifidobacterium levels and markedly promoted Bacteroides abundance (P < 0.05, and P < 0.01, respectively). The fecal metabolomic profile was also substantially altered by the MCD diet: At 2 wk, arachidic acid, hexadecane, palmitic acid, and tetracosane were selected as potential biomarkers that were significantly different in the corresponding control group, and at 4 wk, cholic acid, cholesterol, arachidic acid, tetracosane, and stearic acid were selected.

CONCLUSION

The MCD diet induced persistent alterations in the gut microbiota and metabolome.

Time-dependent changes and association between liver free fatty acids, serum lipid profile and histological features in mice model of nonalcoholic fatty liver disease

BACKGROUND AND AIMS

Methionine-choline deficient (MCD) diet duration necessary for development of non-alcoholic fatty liver disease (NAFLD) and the dynamic of lipid profile and fatty acids are not completely established. The study examined dynamics and association between liver free fatty acids (FFA), serum lipid profile and liver morphological changes on MCD diet-induced NAFLD in mice.

METHODS

Male C57BL/6 mice (n = 28) were divided into four groups (n = 7 per group): control: fed with standard chow, MCD diet-fed groups: 2, 4 or 6 weeks. After treatment, liver and blood samples were taken for histopathology, serum lipid profile, and liver FFA composition.

RESULTS

Hepatic FFA profile showed a decrease in saturated acids, arachidonic and docosahexaenoic acid, whereas proportions of docosapentaenoic, oleic and linoleic acid were increased. Total cholesterol, HDL and triglycerides progressively decreased, whereas LDL level progressively increased. Focal fatty change in the liver appeared after 2 weeks, whereas diffuse fatty change with severe inflammation and ballooned hepatocytes were evident after 6 weeks.

CONCLUSIONS

Six-week diet model may be appropriate for investigation of the role of lipotoxicity in the progression of NAFLD. Therefore, supplementation with n-3 polyunsaturated acid like DHA, rather than DPA, especially in the initial stage of fatty liver disease, may potentially have preventive effects and alleviate development of NAFLD/NASH and may also potentially reduce cardiovascular risk by moderating dyslipidemia.