scholarly journals Bile Acid Sequestrant, Sevelamer Ameliorates Hepatic Fibrosis with Reduced Overload of Endogenous Lipopolysaccharide in Experimental Nonalcoholic Steatohepatitis

2020 ◽  
Vol 8 (6) ◽  
pp. 925 ◽  
Author(s):  
Yuki Tsuji ◽  
Kosuke Kaji ◽  
Mitsuteru Kitade ◽  
Daisuke Kaya ◽  
Koh Kitagawa ◽  
...  

Despite the use of various pharmacotherapeutic strategies, fibrosis due to nonalcoholic steatohepatitis (NASH) remains an unsatisfied clinical issue. We investigated the effect of sevelamer, a hydrophilic bile acid sequestrant, on hepatic fibrosis in a murine NASH model. Male C57BL/6J mice were fed a choline-deficient, L-amino acid-defined, high-fat (CDHF) diet for 12 weeks with or without orally administered sevelamer hydrochloride (2% per diet weight). Histological and biochemical analyses revealed that sevelamer prevented hepatic steatosis, macrophage infiltration, and pericellular fibrosis in CDHF-fed mice. Sevelamer reduced the portal levels of total bile acid and inhibited both hepatic and intestinal farnesoid X receptor activation. Gut microbiome analysis demonstrated that sevelamer improved a lower α-diversity and prevented decreases in Lactobacillaceae and Clostridiaceae as well as increases in Desulfovibrionaceae and Enterobacteriaceae in the CDHF-fed mice. Additionally, sevelamer bound to lipopolysaccharide (LPS) in the intestinal lumen and promoted its fecal excretion. Consequently, the sevelamer treatment restored the tight intestinal junction proteins and reduced the portal LPS levels, leading to the suppression of hepatic toll-like receptor 4 signaling pathway. Furthermore, sevelamer inhibited the LPS-mediated induction of fibrogenic activity in human hepatic stellate cells in vitro. Collectively, sevelamer inhibited the development of murine steatohepatitis by reducing hepatic LPS overload.

2021 ◽  
Vol 22 (12) ◽  
pp. 6468
Author(s):  
Hana Lastuvkova ◽  
Fatemeh Alaei Faradonbeh ◽  
Jolana Schreiberova ◽  
Milos Hroch ◽  
Jaroslav Mokry ◽  
...  

Bile acids (BA) play a significant role in the pathophysiology of nonalcoholic steatohepatitis (NASH). The present study evaluates the modulation of bile acid metabolomics by atorvastatin, a cholesterol-lowering agent commonly used to treat cardiovascular complications accompanying NASH. NASH was induced in mice by 24 weeks of consuming a high–saturated fat, high-fructose, and high-cholesterol diet (F), with atorvastatin administered orally (20 mg/kg/day) during the last three weeks. Biochemical and histological analyses confirmed the effectiveness of the F diet in inducing NASH. Untreated NASH animals had significantly reduced biliary secretion of BA and increased fecal excretion of BA via decreased apical sodium-dependent bile salt transporter (Asbt)-mediated reabsorption. Atorvastatin decreased liver steatosis and inflammation in NASH animals consistently with a reduction in crucial lipogenic enzyme stearoyl–coenzyme A (CoA) desaturase-1 and nuclear factor kappa light chain enhancer of activated B-cell pro-inflammatory signaling, respectively. In this group, atorvastatin also uniformly enhanced plasma concentration, biliary secretion and fecal excretion of the secondary BA, deoxycholic acid (DCA). However, in the chow diet–fed animals, atorvastatin decreased plasma concentrations of BA, and reduced BA biliary secretions. These changes stemmed primarily from the increased fecal excretion of BA resulting from the reduced Asbt-mediated BA reabsorption in the ileum and suppression of synthesis in the liver. In conclusion, our results reveal that atorvastatin significantly modulates BA metabolomics by altering their intestinal processing and liver synthesis in control and NASH mice.


Author(s):  
Peijie Wu ◽  
Ling Qiao ◽  
Han Yu ◽  
Hui Ming ◽  
Chao Liu ◽  
...  

Cholestasis is a kind of stressful syndrome along with liver toxicity, which has been demonstrated to be related to fibrosis, cirrhosis, even cholangiocellular or hepatocellular carcinomas. Cholestasis usually caused by the dysregulated metabolism of bile acids that possess high cellular toxicity and synthesized by cholesterol in the liver to undergo enterohepatic circulation. In cholestasis, the accumulation of bile acids in the liver causes biliary and hepatocyte injury, oxidative stress, and inflammation. The farnesoid X receptor (FXR) is regarded as a bile acid–activated receptor that regulates a network of genes involved in bile acid metabolism, providing a new therapeutic target to treat cholestatic diseases. Arbutin is a glycosylated hydroquinone isolated from medicinal plants in the genus Arctostaphylos, which has a variety of potentially pharmacological properties, such as anti-inflammatory, antihyperlipidemic, antiviral, antihyperglycemic, and antioxidant activity. However, the mechanistic contributions of arbutin to alleviate liver injury of cholestasis, especially its role on bile acid homeostasis via nuclear receptors, have not been fully elucidated. In this study, we demonstrate that arbutin has a protective effect on α-naphthylisothiocyanate–induced cholestasis via upregulation of the levels of FXR and downstream enzymes associated with bile acid homeostasis such as Bsep, Ntcp, and Sult2a1, as well as Ugt1a1. Furthermore, the regulation of these functional proteins related to bile acid homeostasis by arbutin could be alleviated by FXR silencing in L-02 cells. In conclusion, a protective effect could be supported by arbutin to alleviate ANIT-induced cholestatic liver toxicity, which was partly through the FXR pathway, suggesting arbutin may be a potential chemical molecule for the cholestatic disease.


2019 ◽  
Vol 75 ◽  
pp. 105833
Author(s):  
Xiaohui Wang ◽  
Ting Fu ◽  
Junqiao Wang ◽  
Changyuan Wang ◽  
Kexin Liu ◽  
...  

mBio ◽  
2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Ming-liang Chen ◽  
Long Yi ◽  
Yong Zhang ◽  
Xi Zhou ◽  
Li Ran ◽  
...  

ABSTRACT The gut microbiota is found to be strongly associated with atherosclerosis (AS). Resveratrol (RSV) is a natural phytoalexin with anti-AS effects; however, its mechanisms of action remain unclear. Therefore, we sought to determine whether the anti-AS effects of RSV were related to changes in the gut microbiota. We found that RSV attenuated trimethylamine- N -oxide (TMAO)-induced AS in ApoE −/− mice. Meanwhile, RSV decreased TMAO levels by inhibiting commensal microbial trimethylamine (TMA) production via gut microbiota remodeling in mice. Moreover, RSV increased levels of the genera Lactobacillus and Bifidobacterium , which increased the bile salt hydrolase activity, thereby enhancing bile acid (BA) deconjugation and fecal excretion in C57BL/6J and ApoE −/− mice. This was associated with a decrease in ileal BA content, repression of the enterohepatic farnesoid X receptor (FXR)-fibroblast growth factor 15 (FGF15) axis, and increased cholesterol 7a-hydroxylase (CYP7A1) expression and hepatic BA neosynthesis. An FXR antagonist had the same effect on FGF15 and CYP7A1 expression as RSV, while an FXR agonist abolished RSV-induced alterations in FGF15 and CYP7A1 expression. In mice treated with antibiotics, RSV neither decreased TMAO levels nor increased hepatic BA synthesis. Additionally, RSV-induced inhibition of TMAO-caused AS was also markedly abolished by antibiotics. In conclusion, RSV attenuated TMAO-induced AS by decreasing TMAO levels and increasing hepatic BA neosynthesis via gut microbiota remodeling, and the BA neosynthesis was partially mediated through the enterohepatic FXR-FGF15 axis. IMPORTANCE Recently, trimethylamine- N -oxide (TMAO) has been identified as a novel and independent risk factor for promoting atherosclerosis (AS) partially through inhibiting hepatic bile acid (BA) synthesis. The gut microbiota plays a key role in the pathophysiology of TMAO-induced AS. Resveratrol (RSV) is a natural phytoalexin with prebiotic benefits. A growing body of evidence supports the hypothesis that phenolic phytochemicals with poor bioavailability are possibly acting primarily through remodeling of the gut microbiota. The current study showed that RSV attenuated TMAO-induced AS by decreasing TMAO levels and increasing hepatic BA neosynthesis via gut microbiota remodeling. And RSV-induced hepatic BA neosynthesis was partially mediated through downregulating the enterohepatic farnesoid X receptor-fibroblast growth factor 15 axis. These results offer new insights into the mechanisms responsible for RSV’s anti-AS effects and indicate that the gut microbiota may become an interesting target for pharmacological or dietary interventions to decrease the risk of developing cardiovascular diseases.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Teayoun Kim ◽  
Shelly R Nason ◽  
Jessica Antipenko ◽  
Natalie Presedo ◽  
Brian Finan ◽  
...  

Abstract Glucagon, an essential regulator of glucose and lipid metabolism, also promotes weight loss in obese mice. We have shown that hepatic Farnesoid X Receptor (FXR, a bile acid receptor) and bile acids (BA) play an important role in the anti-obesity effect of glucagon in mice. Specifically, glucagon-receptor (GCGR) agonism is a potent regulator of BA metabolism, increasing total plasma BA levels and preferentially raising cholic and chenodeoxycholic acid levels. These findings led us to hypothesize that BA, signaling via hepatic FXR, contributes to GCGR-stimulated weight loss. Furthermore, we reasoned that BA sequestration may impair GCGR-mediated weight loss by reducing the availability of BA to stimulate FXR-action. Thus, to elucidate the role of BA in GCGR-mediated weight loss, we utilized anion-exchange BA-binding resins (BARS; Cholestyramine and Colesevelam) to prevent intestinal (ileal) re-uptake and reduce plasma total cholesterol, LDL, and BAs via fecal excretion. Diet-induced obese (DIO) C57Bl/6J mice were randomized to groups matched for body-weight and administered daily GCGR agonism (IUB288, 10 nmol/kg, s.c.) or vehicle, in the presence or absence of BARS. Consistent with our prior findings, IUB288-treatment reduced body weight in DIO mice. Counter to our original hypothesis, IUB288+Cholestyramine (3% in high fat diet, HFD [58% kcal%]) enhanced IUB288-stimulated weight loss. Similar body-weight loss effects following combined IUB288 and BARS treatment were replicated both at a lower dose of Cholestyramine (1.5% in HFD), as well as in combination with both low- (2% in HFD) and high- (4% in HFD) dose Colesevelam. IUB288-stimulated weight loss is accompanied by suppression of food intake (FI), while Colesevelam alone did not significantly lower FI at either dose (2 or 4% in HFD). However, 4% Colesevelam with IUB288 completely suppressed FI, while 2% Colesevelam stimulated a reduced, though not complete suppression. GCGR agonism is a potent stimulus of weight loss; however, its impairment of glucose tolerance reduces its value as a monotherapy. Excitingly, Cholestyramine (3% in HFD) rescued IUB288-induced glucose intolerance, restoring glucose excursion to levels observed in control (vehicle-treated) mice. Together these studies suggest BARS may enhance the anti-obesity effect of GCGR agonism, beneficially regulate feeding behaviors, and prevent GCGR-stimulated glucose dysregulation in DIO mice. Furthermore, these studies argue that GCGR agonsim combined with BARS treatment may represent a novel therapeutic approach for obesity and obesity-associated glucose intolerance.


2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Kavita S Jadhav ◽  
Yang Xu ◽  
Yanqiao Zhang

Objectives: Activation of the bile acid (BA) receptors farnesoid X receptor (FXR) or TGR5 has beneficial effects on metabolic homeostasis. However, activation of FXR may increase obesity and activation of TGR5 has little effect on lipid metabolism. As such, dual activation of FXR and TGR5 appears to be a more attractive approach for treatment of common metabolic disorders. So far, the role of BA receptor activation in metabolic regulation is not well characterized. Methods: We utilized wild-type (WT) mice, Tgr5 -/- mice, Fxr -/- mice, Apoe -/- mice and Shp -/- mice to investigate whether and how BA receptor activation by INT-767, a semisynthetic agonist for both FXR and TGR5, can prevent or reverse diet-induced metabolic disorders. Results: INT-767 reversed HFD-induced obesity and hyperglycemia in a TGR5-dependent manner and inhibited the development of atherosclerosis and non-alcoholic fatty liver disease (NAFLD). Mechanistically, INT-767 improved lipid homeostasis by activation of FXR and increased energy expenditure. Furthermore, activation of FXR inhibited several lipogeneic genes in the liver. We identified peroxisome proliferation-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (CEBPα) as novel downstream targets of FXR. FXR inhibited PPARγ expression by inducing SHP (small heterodimer partner) whereas the inhibition of CEBPα by FXR is SHP-independent. Conclusions: BA receptor activation can prevent and reverse obesity, NAFLD and atherosclerosis by specific activation of FXR or TGR5. Our data suggest that compared of activation of FXR or TGR5 alone, dual activation of both FXR and TGR5 is a more attractive strategy for treatment of common metabolic disorders. Key words: FXR; TGR5; Atherosclerosis; Obesity; NAFLD; Lipogenesis


2021 ◽  
Vol 7 (30) ◽  
pp. eabg1371
Author(s):  
Jia Wen ◽  
Gilberto Padilla Mercado ◽  
Alyssa Volland ◽  
Heidi L. Doden ◽  
Colin R. Lickwar ◽  
...  

Bile salt synthesis, secretion into the intestinal lumen, and resorption in the ileum occur in all vertebrate classes. In mammals, bile salt composition is determined by host and microbial enzymes, affecting signaling through the bile salt–binding transcription factor farnesoid X receptor (Fxr). However, these processes in other vertebrate classes remain poorly understood. We show that key components of hepatic bile salt synthesis and ileal transport pathways are conserved and under control of Fxr in zebrafish. Zebrafish bile salts consist primarily of a C27 bile alcohol and a C24 bile acid that undergo multiple microbial modifications including bile acid deconjugation that augments Fxr activity. Using single-cell RNA sequencing, we provide a cellular atlas of the zebrafish intestinal epithelium and uncover roles for Fxr in transcriptional and differentiation programs in ileal and other cell types. These results establish zebrafish as a nonmammalian vertebrate model for studying bile salt metabolism and Fxr signaling.


2010 ◽  
Vol 298 (3) ◽  
pp. G419-G424 ◽  
Author(s):  
Quan Shang ◽  
Monica Saumoy ◽  
Jens Juul Holst ◽  
Gerald Salen ◽  
Guorong Xu

Bile acid sequestrants have been shown to lower glucose levels in patients with type 2 diabetes. To investigate how colesevelam (CL) HCl improves hyperglycemia, studies were conducted in diet-induced obesity (F-DIO) rats, which develop insulin resistance when fed a high-energy (high fat/high sucrose) diet (HE). The rats were fed HE; HE + 2% CL; HE + 0.02% SC-435 (SC), an apical sodium-dependent bile acid transporter inhibitor; and regular chow (controls). After 4 wk of treatment, both in the HE group and the SC + HE group, plasma glucose and insulin levels remained elevated compared with baseline values throughout an oral glucose tolerance test (OGTT). In contrast, in the CL + HE group, plasma glucose levels returned to baseline by the end of the test, and insulin peaked in 15–30 min and then returned to baseline. CL induced release of glucagon-like peptide-1 (GLP-1) because the area under the curve of plasma total GLP-1 in the CL + HE group was significantly greater than in the HE group during the OGTT. Bile acid concentrations in the portal blood did not decrease in the HE group but declined significantly both in the CL + HE and SC + HE groups with reduced farnesoid X receptor activation compared with controls. We concluded that CL reduces plasma glucose levels by improving insulin resistance in this rat model. It is unlikely that the improvement is attributable to decreased bile acid flux to the liver but is likely secondary to induced GLP-1 secretion, which improves insulin release.


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