Ganoderma lucidum polysaccharide ameliorates cholesterol gallstone formation by modulating cholesterol and bile acid metabolism in an FXR-dependent manner.

BACKGROUND: Cholesterol gallstone (CG) disease is a worldwide common disease characterized by cholesterol supersaturation in gallbladder bile. Ganoderma lucidum polysaccharide (GLP) has been shown to possess various beneficial effects against metabolic disorders. However, the role and underlying mechanism of GLP in CG formation are still unknown. This study aimed to determine the role of GLP in ameliorating lithogenic diet (LD)-induced CG formation. METHODS: Mice were fed either a normal chow diet, a LD, or LD supplemented with GLP. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to detect the expression of genes involved in cholesterol and bile acid (BA) metabolism. The BA concentrations in the ileum were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The microbiota in cecal contents were characterized using 16S ribosomal RNA (16S rRNA) gene sequencing. RESULTS: GLP effectively alleviated CG formation induced by LD. Specifically, GLP reduced the total cholesterol (TC) levels, increased the total BA levels, and decreased the cholesterol saturation index (CSI) in gallbladder bile. The protective effect of GLP was attributed to the inhibition of farnesoid X receptor (FXR) signaling, increased hepatic BA synthesis and decreased hepatic cholesterol synthesis and secretion. GLP also altered the BA composition in the ileum, reducing FXR-agonistic BAs and increasing FXR-antagonistic BAs, which may contribute to the inhibition of intestinal FXR signaling. Additionally, GLP improved dysbiosis of the intestinal flora and reduced the serum levels of hydrogen sulfide (H2S), a bacterial metabolite that can induce hepatic FXR, thereby inhibiting hepatic FXR signaling. Moreover, the protective effect of GLP against CG formation could be reversed by both the global and gut-restricted FXR agonists. CONCLUSIONS: Taken together, GLP ameliorates CG formation by regulating cholesterol and BA metabolism in an FXR-dependent manner. Our study demonstrates that GLP may be a potential strategy for the prevention against CG disease.

Discovery and exploration of novel somatostatin receptor subtype 5 (SSTR5) antagonists for the treatment of cholesterol gallstones.

The shortage of cholesterol gallstones treatment intensifies the need to discover of effective small molecule drugs. Clinical follow-up and studies have found that activation of somatostatin receptor subtype 5 (SSTR5) reduce gallbladder contraction and thus increase the risk of cholesterol gallstones, implying that antagonizing SSTR5 may promote gallbladder emptying and reduce the formation of gallstones. Herein, we discovered novel SSTR5 antagonists and firstly investigated its effects on cholesterol gallstone. From loperamide, a reported seed structure with micromole activity, we identified optimal compound 23 as an SSTR5 antagonist exhibiting single-digit nanomolar potency, low hERG inhibition and oral availability. Further in vivo evaluation revealed that 23 significantly promoted gallbladder emptying. Moreover, in a mouse cholesterol gallstone model, 23 (3 mg/kg) effectively reduced the cholesterol gallstones formation, showing better efficacy than the clinical first-line drug UDCA (60 mg/kg), providing a new insight into the development of anti-gallstone drugs.

Exploration of molecular interactions between scoparone and associated compounds with Constitutive androstane receptor (CAR) leading to gallstone prevention: an in silico investigation.

Scoparone (6, 7 dimethylesculetin) is a biologically active compound derived from the herb Artemisia capillaris having anti-inflammatory, anti-lipemic, and anti-allergic roles. Activation of the constitutive androstane receptor (CAR) in primary hepatocytes of both wild-type and humanized CAR mice by scoparone, accelerates bilirubin and cholesterol clearance in vivo. This can prevent gallstones which is a dreaded gastrointestinal disease. To date, surgery is regarded as the gold standard for treating gallstones. The molecular interactions between scoparone and CAR leading to gallstone prevention are not yet explored. In this study, we have analyzed these interactions through an insilico approach. After extracting the CAR structures (mice and human) from the protein databank and 6, 7-dimethylesuletin from PubChem, energy minimization of both the receptors was done to make them stable followed by docking. Next, a simulation was performed to stabilize the docked complexes. Through docking, H-bonds and pi-pi interactions were found in the complexes, which imply a stable interaction, thus activating the CAR. A similarity search for scoparone was performed and the selected compounds were docked with the CAR receptors. Esculentin acetate and scopoletin acetate interacted with human CAR through pi-alkyl and H-bond respectively. While Fraxidin methyl ether, fraxinol methyl ether, and 6, 7 diethoxycoumarin interacted with mice CAR through H-bond and Pi-Pi T-shaped bonds. The selected complexes were simulated further. Our results are in accordance with the hypothesis in the literature. We have also analyzed the drug likeliness, absorption, non-carcinogenicity, and other properties of scoparone which can support further in vivo studies.Communicated by Ramaswamy H. Sarma.

Research progress on the immune microenvironment of the gallbladder in patients with cholesterol gallstones.

Cholesterol gallstones are very common in hepatobiliary surgery and have been studied to a certain extent by doctors worldwide for decades. However, the mechanism of cholesterol gallstone formation is not fully understood, so there is currently no completely effective drug for the treatment and prevention of cholesterol gallstones. The formation and development of cholesterol gallstones are caused by a variety of genetic and environmental factors, among which genetic susceptibility, intestinal microflora disorders, impaired gallbladder motility, and immune disorders are important in the pathogenesis of cholesterol gallstones. This review focuses on recent advances in these mechanisms. We also discuss some new targets that may be effective in the treatment and prevention of cholesterol gallstones, which may be hot areas in the future.

FXR Signaling-Mediated Bile Acid Metabolism Is Critical for Alleviation of Cholesterol Gallstones by Lactobacillus Strains.

Cholesterol gallstone (CGS) disease is characterized by an imbalance in bile acid (BA) metabolism and is closely associated with gut microbiota disorders. However, the role and mechanism by which probiotics targeting the gut microbiota attenuate cholesterol gallstones are still unknown. In this study, Limosilactobacillus reuteri strain CGMCC 17942 and Lactiplantibacillus plantarum strain CGMCC 14407 were individually administered to lithogenic-diet (LD)-fed mice for 8 weeks. Both Lactobacillus strains significantly reduced LD-induced gallstones, hepatic steatosis, and hyperlipidemia. These strains modulated BA profiles in the serum and liver, which may be responsible for the activation of farnesoid X receptor (FXR). At the molecular level, L. reuteri and L. plantarum increased ileal fibroblast growth factor 15 (FGF15) and hepatic fibroblast growth factor receptor 4 (FGFR4) and small heterodimer partner (SHP). Subsequently, hepatic cholesterol 7α-hydroxylase (CYP7A1) and oxysterol 7α-hydroxylase (CYP7B1) were inhibited. Moreover, the two strains enhanced BA transport by increasing the levels of hepatic multidrug resistance-associated protein homologs 3 and 4 (Mrp3/4), hepatic multidrug resistance protein 2 (Mdr2), and the bile salt export pump (BSEP). In addition, both L. reuteri and L. plantarum reduced LD-associated gut microbiota dysbiosis. L. reuteri increased the relative abundance of Muribaculaceae, while L. plantarum increased that of Akkermansia. The changed gut microbiota was significantly negatively correlated with the incidence of cholesterol gallstones and the FXR-antagonistic BAs in the liver and serum and with the FXR signaling pathways. Furthermore, the protective effects of the two strains were abolished by both global and intestine-specific FXR antagonists. These findings suggest that Lactobacillus might relieve CGS through the FXR signaling pathways. IMPORTANCE Cholesterol gallstone (CGS) disease is prevalent worldwide. None of the medical options for prevention and treatment of CGS disease are recommended, and surgical management has a high rate of recurrence. It has been reported that the factors involved in metabolic syndrome are highly connected with CGS formation. While remodeling of dysbiosis of the gut microbiome during improvement of metabolic syndrome has been well studied, less is known about prevention of CGS formation after regulating the gut microbiome. We used the lithogenic diet (LD) to induce an experimental CGS model in C57BL/6J mice to investigate protection against CGS formation by Limosilactobacillus reuteri strain CGMCC 17942 and Lactiplantibacillus plantarum strain CGMCC 14407. We found that these L. reuteri and L. plantarum strains altered the bile acid composition in mice and improved the dysbiosis of the gut microbiome. These two Lactobacillus strains prevented CGS formation by fully activating the hepatic and ileal FXR signaling pathways. They could be a promising therapeutic strategy for treating CGS or preventing its recurrence.

Evaluation of gallstone classification and their diagnosis through serum parameters as emerging tools in treatment: a narrative review.

The treatment of gallstones is a matter of real concern as they may cause gallbladder cancer if not properly attended to. Evaluating the classification of gallstones can give major clues in their treatment as it will decide their etiology, chemical composition, and pathogenesis. Also, serum parameters have emerged as an efficient tool for diagnosing gallstones. They can be probed to evaluate different biochemicals and the changes in their levels in gallstone patients which can be correlated with early prediction of the formation of gallstones. In the present review, a thorough search of the available literature was done starting from the earliest approaches for the classification of gallstones up to the recent advancements. The alteration in the level of serum parameters was also studied in gallstone patients so that it can act as a potential diagnostic tool for early detection of gallstone formation. The earliest classification of gallstones was done in 1896 by Naunyn. He classified them into pure cholesterol stones, laminated cholesterol stones, ordinary gallbladder stones, mixed bilirubin stones, and rare forms. The most recent classification of gallstones was done by Peter et al in 2020 and they classified them as pure, mixed, composite cholesterol, carbonate stones, black and brown pigment stones. The altered of levels of serum parameters was analyzed by Reuben (1985) and in recent times by Peter et al (2020). The various serum parameters studied were as RDW-CV test (red blood cell distribution width), PCT (prolactin) test, MPV (mean platelet count), LYM (lymphocyte) test, and EOS (eosinophil and eosinophil count test). Also, we discussed some practical considerations for gallstones that can be taken into account for gallstone prevention and diagnosis. Further research is required to detect gallstone type in the gallbladder by using the alteration in the levels of serum parameters.

Recent advances, novel targets and treatments for cholelithiasis; a narrative review.

Cholelithiasis is a common and frequent condition all over the world with a high prevalence rate in western countries. Individuals with cholesterol gallstone disease experience intense gastrointestinal symptoms and have a high risk of developing comorbidities like cholecystitis, Gall bladder (GB) cancer and pancreatitis. Multiple risk factors associated with cholesterol gallstones include but not limited to genetics, dietary habits, lifestyle changes, comorbid conditions and various drugs. These factors may lead to alteration in bile, cholesterol & phospholipids homeostasis in the GB, intestine and hepatocytes culminating in cholesterol gallstones formation. Surgical (cholecystectomy) and non-surgical (oral dissolution therapy) treatments are available for the disease, albeit with certain complications and high treatment cost. Thus, there is a need for interventions, complementary or alternative therapies for the treatment and prevention of cholesterol gallstones. Currently available drug therapies used for cholesterol gallstones include statins and ezetimibe. Many patients consider traditional herbal practitioners due to their promise of non-invasive and pain free management of gall stones. This present a positive shift towards generally acceptable safety and cost effectiveness of herbal treatment warranting extensive research for alternative or complementary choice such as herbal plants as an emerging area for their potential therapeutic effects. This review discusses current strategies, latest trends available in the disease pathogenesis, drug development for novel targets, risk management, newer anti-lithogenic drugs and herbal plants that target the different aspects of the disease.

Symptomatic gallstones and HIV in black South African women: Changing trends of gallstone disease?

BACKGROUND: The incidence of metabolic disorders in human immunodeficiency virus (HIV) endemic settings is a prevailing burden in developing countries. Cholesterol homeostasis and fat metabolism are altered by HIV and antiretroviral therapy (ART), thereby possibly contributing to complications such as gallstone formation. OBJECTIVES: The aim of this study was to evaluate established risk factors for the formation of cholesterol gallstones in black South African women living with HIV (WLHIV). METHOD: A case series study was conducted of all black South African women undergoing cholecystectomy for gallstone disease over a 1-year period at King Edward VIII Hospital, Durban, South Africa. Age, body mass index (BMI), family history of gallstones, oestrogen exposure and lipograms were compared between WLHIV and uninfected women. Categorical variables were tested using either the Fisher's exact test or Pearson's chi-square test. Means were compared using independent t-tests. For non-normally distributed data, the Mann-Whitney U test was used. Statistical tests were two-sided, and p-values of less than 0.05 were considered statistically significant. RESULTS: A total of 52 patients were assessed, 34 HIV-uninfected and 18 WLHIV. The median age of WLHIV versus the uninfected women was 35 and 50 years, respectively, (p = 0.015). A statistically significant number of uninfected women were in the overweight/obese category (BMI > 25 kg/m2) compared to the normal weight category (BMI < 25 kg/m2) (p < 0.001). The number of obese WLHIV did not reach statistical significance. CONCLUSION: The age of occurrence of gallstone disease amongst black South African WLHIV was significantly lower and fewer women were obese compared with the uninfected women with gallstone disease. These findings differ from known gallstone risk factors in other populations and in uninfected black South African women. This could be attributed to the metabolic alterations caused by HIV infection itself and/or to the long-term use of ART. Larger cohort studies are required to elucidate the role of HIV and ART in cholestatic disease.

Cholesterol gallstones: Focusing on the role of interstitial Cajal-like cells.

Cholesterol gallstone (CG) is a common, frequent biliary system disease in China, with a complex and multifactorial etiology. Declined gallbladder motility reportedly contributes to CG pathogenesis. Furthermore, interstitial Cajal-like cells (ICLCs) are reportedly present in human and guinea pig gallbladder tissue. ICLCs potentially contribute to the regulation of gallbladder motility, and aberrant conditions involving the loss of ICLCs and/or a reduction in its pacing potential and reactivity to cholecystokinin may promote CG pathogenesis. This review discusses the association between ICLCs and CG pathogenesis and provides a basis for further studies on the functions of ICLCs and the etiologies of CG.

Curcumin inhibits the proteolytic process of SREBP-2 by first inhibiting the expression of S1P rather than directly inhibiting SREBP-2 expression.

Many studies have demonstrated that curcumin can downregulate mRNA levels of sterol regulatory element-binding proteins (SREBP-2); however, our study did not find similar results. This study was designed to demonstrate that curcumin inhibits the proteolytic process of SREBP-2 by first inhibiting the expression of membrane-bound transcription factor site-1 protease (S1P) rather than directly inhibiting SREBP-2 expression. After curcumin treatment, Caco-2 cells were collected to observe the dose- and time-dependent dynamics of precursor and mature SREBP-2, transcription factor-specific protein 1 (SP-1), and SREBP cleavage-activating protein (SCAP). After curcumin treatment, SREBP-2 distribution was detected in the cells and S1P protein expression was examined. Curcumin could downregulate mRNA levels of SREBP2, SP-1 and SCAP, but it did not simultaneously downregulate the expression of precursor SREBP-2 (pSREBP-2) and SCAP. Curcumin can inhibit the proteolytic process of SREBP-2, reduce the production of mature SREBP-2 (mSREBP-2), and change the cellular distribution of SREBP-2. The inhibitory effect of curcumin on SP-1 protein expression is short-acting. Curcumin could downregulate the mRNA and protein expression of S1P, but has no obvious inhibitory effect on the mRNA and protein expression of S2P (site-2 protease). Curcumin can inhibit the SREBP-2 proteolytic process to reduce mSREBP-2 which functions as a transcription factor, affecting the regulation of cholesterol metabolism-related genes. Curcumin does not directly inhibit the expression of mSREBP-2 protein, and it has no such inhibitory effect for at least a short period of time, although curcumin does reduce the amount of mSREBP-2 protein. S1P is a key protease in the hydrolysis of pSREBP-2 into mSREBP-2. Therefore, curcumin may decrease the amount of mSREBP-2 by directly inhibiting the expression of S1P mRNA and protein.