Modulatory effect of camel milk on intestinal microbiota of mice with non-alcoholic fatty liver disease

Astaxanthin could regulate the gut-kidney axis to mitigate kidney injury in high-fat diet/streptozotocin-induced diabetic mice

Accumulating evidences have shown the beneficial effects of astaxanthin (AST) supplementation on metabolic diseases prevention and treatment. The goal of present study was to reveal the favorable interactions among AST supplementation, gut microbiota, and kidneys in vivo, so as to attenuate kidney impairment in diabetic mice. Twenty C57BL/6J mice were assigned to a normal control group and a diabetic model group induced by a high-fat diet plus low-dose streptozotocin, and then the diabetic mice were fed with a high-fat diet without or with AST [0.01% (AST_a) or 0.02% (AST_b)] for 12 weeks. When compared to the diabetes kidney disease (DKD) group, AST supplementation delayed the renal pathological progression, reduced fasting blood glucose (AST_b: 1.53-fold, p<0.05), repressed levels of lipopolysaccharide (LPS; AST_a: 1.24-fold, p=0.008; AST_b: 1.43-fold, p<0.001) and TMAO (AST_a: 1.51-fold, p=0.001; AST_b: 1.40-fold, p=0.003), inhibited IL-6 (AST_a: 1.40-fold, p=0.004; AST_b: 1.57-fold, p=0.001) and reactive oxygen species (ROS; AST_a: 1.30-fold, p=0.004; AST_b: 1.53-fold, p<0.001), as well as regulated the Sirt1/PGC-1α/NFκB p65 signaling pathway. Moreover, the results of 16S rRNA gene-based Illumina deep sequencing in each group revealed that dietary AST supplementation also favorably modulated the gut microbiota compared with the DKD group, as evidenced by the inhibition of the harmful bacteria Clostridium_sensu_stricto_1, Romboutsia, and Coriobacteriaceae_UCG-002, and the enhancement of the probiotics such as Lachnospiraceae_NK4A136_group, Roseburia, and Ruminococcaceae. Taken together, dietary AST supplementation could protect kidneys against inflammation and oxidative stress by adjusting the gut-kidney axis in diabetic mice.

Kluyveromyces marxianus supplementation ameliorates alcohol-induced liver injury associated with the modulation of gut microbiota in mice

The aim of this study was to evaluate the intervention effect of the potential probiotic Kluyveromyces marxianus YG-4 isolated from Tibetan kefir grains on alcoholic liver disease (ALD). Eight-week-old male C57BL/6J mice were fed with a Lieber-DeCarli (LDC) diet containing ethanol with a progressively increasing concentration from 1% to 4% (vol/vol) to establish an ALD mouse model. Our results suggested that K. marxianus treatment improved ALD, as demonstrated by the reduction of serum ALT and AST levels and the suppression of TLR4/NF-κB-mediated inflammatory response in the liver. K. marxianus administration significantly elevated antioxidant activities of SOD, CAT and GSH-Px, and reduced the MDA level in mice. K. marxianus supplementation repaired the gut barrier by increasing tight junction proteins and the number of goblet cells in the colon of ALD mice. In addition, treatment with K. marxianus restored alcohol-induced gut dysbiosis. Specifically, K. marxianus administration depleted the abundance of Lactobacillus, Coriobacteriaceae_UCG-002 and Candida, while increased that of Allobaculum, Dubosiella and Epicoccum in mice. Our findings open new possibilities for K. marxianus application in ALD treatment.

Effects of cholesterol-lowering probiotics on non-alcoholic fatty liver disease in FXR gene knockout mice

Background/aims

Some studies showed that probiotics could improve the composition and structure of gut microbiota. Changes in the gut microbiota may alter bile acid (BAs) composition and kinetics, improving non-alcoholic fatty liver disease (NAFLD). However, it still needs to be clarified how probiotics improve both the metabolism of BAs and NAFLD. This study aimed to reveal the regulatory mechanisms of cholesterol-lowering (CL) probiotics on NAFLD from aspects involved in BA metabolism in FXR gene knockout (FXR-/-) mice.

Methods

FXR-/- male mice were randomly divided into three groups based on different interventions for 16 weeks, including normal diet (ND), high-fat diet (HFD), and probiotic intervention in the HFD (HFD+P) group. 16s rDNA sequencing and ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) were utilized to analyze the changes in gut microbiota and fecal bile acids in mice.

Results

We found that the intervention of the CL probiotics improved liver lipid deposition and function in HFD-induced NAFLD mice by decreasing the levels of total cholesterol (TC; p = 0.002) and triglyceride (TG; p = 0.001) in serum, as well as suppressing liver inflammation, such as interleukin-1 beta (IL-1β; p = 0.002) and tumor necrosis factor-alpha (TNF-α; p < 0.0001). 16S rDNA sequencing and metabolomic analyses showed that probiotics effectively reduced the abundance of harmful gut microbiota, such as Firmicutes (p = 0.005), while concomitantly increasing the abundance of beneficial gut microbiota in NAFLD mice, such as Actinobacteriota (p = 0.378), to improve NAFLD. Compared with the ND group, consuming an HFD elevated the levels of total BAs (p = 0.0002), primary BAs (p = 0.017), and secondary BAs (p = 0.0001) in mice feces, while the intervention with probiotics significantly reduced the increase in the levels of fecal total bile acids (p = 0.013) and secondary bile acids (p = 0.017) induced by HFD.

Conclusion

The CL probiotics were found to improve liver function, restore microbiota balance, correct an abnormal change in the composition and content of fecal bile acids, and repair the damaged intestinal mucosal barrier in mice with NAFLD, ultimately ameliorating the condition. These results suggested that CL probiotics may be a promising and health-friendly treatment option for NAFLD.