Publications by authors named "Dominique Rainteau"

57 Publications

TGR5 controls bile acid composition and gallbladder function to protect the liver from bile acid overload.

JHEP Rep 2021 Apr 11;3(2):100214. Epub 2020 Nov 11.

Université Paris Saclay, Faculté des Sciences d'Orsay, INSERM U.1193, bât. 443, 91405, Orsay, France.

Background & Aims: As the composition of the bile acid (BA) pool has a major impact on liver pathophysiology, we studied its regulation by the BA receptor Takeda G protein coupled receptor (TGR5), which promotes hepatoprotection against BA overload.

Methods: Wild-type, total and hepatocyte-specific TGR5-knockout, and TGR5-overexpressing mice were used in: partial (66%) and 89% extended hepatectomies (EHs) upon normal, ursodeoxycholic acid (UDCA)- or cholestyramine (CT)-enriched diet, bile duct ligation (BDL), cholic acid (CA)-enriched diet, and TGR5 agonist (RO) treatments. We thereby studied the impact of TGR5 on: BA composition, liver injury, regeneration and survival. We also performed analyses on the gut microbiota (GM) and gallbladder (GB). Liver BA composition was analysed in patients undergoing major hepatectomy.

Results: The TGR5-KO hyperhydrophobic BA composition was not directly related to altered BA synthesis, nor to TGR5-KO GM dysbiosis, as supported by hepatocyte-specific KO mice and co-housing experiments, respectively. The TGR5-dependent control of GB dilatation was crucial for BA composition, as determined by experiments including RO treatment and/or cholecystectomy. The poor TGR5-KO post-EH survival rate, related to exacerbated peribiliary necrosis and BA overload, was improved by shifting BAs toward a less toxic composition (CT treatment). After either BDL or a CA-enriched diet with or without cholecystectomy, we found that GB dilatation had strong TGR5-dependent hepatoprotective properties. In patients, a more hydrophobic liver BA composition was correlated with an unfavourable outcome after hepatectomy.

Conclusions: BA composition is crucial for hepatoprotection in mice and humans. We indicate TGR5 as a key regulator of BA profile and thereby as a potential hepatoprotective target under BA overload conditions.

Lay Summary: Through multiple experimental approaches in mice, together with a patient study, this work brings some new light on the relationships between biliary homeostasis, gallbladder function, and liver protection. We showed that hepatic bile acid composition is crucial for optimal liver repair, not only in mice, but also in human patients undergoing major hepatectomy.
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http://dx.doi.org/10.1016/j.jhepr.2020.100214DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7872982PMC
April 2021

Anti-Inflammatory Effects of Analogues of -Acyl Homoserine Lactones on Eukaryotic Cells.

Int J Mol Sci 2020 Dec 11;21(24). Epub 2020 Dec 11.

Laboratoire des Biomolécules (LBM), Département de chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.

Background: Since acyl-homoserine lactone (AHL) profiling has been described in the gut of healthy subjects and patients with inflammatory bowel disease (IBD), the potential effects of these molecules on host cells have raised interest in the medical community. In particular, natural AHLs such as the 3-oxo-C12-HSL exhibit anti-inflammatory properties. Our study aimed at finding stable 3-oxo-C12-HSL-derived analogues with improved anti-inflammatory effects on epithelial and immune cells.

Methods: We first studied the stability and biological properties of the natural 3-oxo-C12-HSL on eukaryotic cells and a bacterial reporter strain. We then constructed and screened a library of 22 AHL-derived molecules. Anti-inflammatory effects were assessed by cytokine release in an epithelial cell model, Caco-2, and a murine macrophage cell line, RAW264.7, (respectively, IL-8 and IL-6) upon exposure to the molecule and after appropriate stimulation (respectively, TNF-α 50 ng/mL and IFN-γ 50 ng/mL, and LPS 10 ng/mL and IFN-γ 20 U/mL).

Results: We found two molecules of interest with amplified anti-inflammatory effects on mammalian cells without bacterial-activating properties in the reporter strain. The molecules furthermore showed improved stability in biological medium compared to the native 3-oxo-C12-HSL.

Conclusions: We provide new bio-inspired AHL analogues with strong anti-inflammatory properties that will need further study from a therapeutic perspective.
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http://dx.doi.org/10.3390/ijms21249448DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7764250PMC
December 2020

Distinct Postprandial Bile Acids Responses to a High-Calorie Diet in Men Volunteers Underscore Metabolically Healthy and Unhealthy Phenotypes.

Nutrients 2020 Nov 19;12(11). Epub 2020 Nov 19.

Institut National de la Santé et de la Recherche Médicale (INSERM, UMR_S 1166-ICAN), Research Institute of Cardiovascular Disease, Metabolism and Nutrition, Faculté de Médecine-Hôpital Pitié-Salpêtrière, Sorbonne Université, F-75013 Paris, France.

Bile acids (BAs) regulate dietary lipid hydrolysis and absorption in the proximal intestine. Several studies have highlighted a determinant role of circulating levels and/or metabolism of BAs in the pathogenesis of major cardiometabolic diseases. Whether changes in BA profiles are causative or are consequence of these diseases remains to be determined. Healthy male volunteers (n = 71) underwent a postprandial exploration following consumption of a hypercaloric high fat typical Western meal providing 1200 kcal. We investigated variations of circulating levels of 28 BA species, together with BA synthesis marker 7α-hydroxy-4-cholesten-3-one (C4) over an approximately diurnal 12 h period. Analysis of BA variations during the postprandial time course revealed two major phenotypes with opposite fluctuations, i.e., circulating levels of each individual species of unconjugated BAs were reduced after meal consumption whereas those of tauro- and glyco-conjugated BAs were increased. By an unbiased classification strategy based on absolute postprandial changes in BA species levels, we classified subjects into three distinct clusters; the two extreme clusters being characterized by the smallest absolute changes in either unconjugated-BAs or conjugated-BAs. Finally, we demonstrated that our clustering based on postprandial changes in BA profiles was associated with specific clinical and biochemical features, including postprandial triglyceride levels, BMI or waist circumference. Altogether, our study reveals that postprandial profiles/patterns of BAs in response to a hypercaloric high fat challenge is associated with healthy or unhealthy metabolic phenotypes that may help in the early identification of subjects at risk of developing metabolic disorders.
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http://dx.doi.org/10.3390/nu12113545DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7699492PMC
November 2020

Biochemical Diagnosis of Bile Acid Diarrhea: Prospective Comparison With the 75Seleno-Taurohomocholic Acid Test.

Am J Gastroenterol 2020 12;115(12):2086-2094

Department of Internal Medicine, Zealand University Hospital, Koege, Denmark.

Introduction: The diagnosis of bile acid diarrhea is often missed because the availability of the seleno-taurohomocholic acid (SeHCAT) test is limited. We aimed to compare the biomarkers 7α-hydroxy-4-cholesten-3-one (C4) and fibroblast growth factor 19 (FGF19) with the SeHCAT test.

Methods: Patients with chronic diarrhea without intestinal resection referred for SeHCAT were prospectively recruited for this diagnostic accuracy study. Blood was sampled at fasting and after a stimulation meal with chenodeoxycholic acid. SeHCAT retention ≤10% defined bile acid diarrhea and >10% defined miscellaneous diarrhea. Receiver operating characteristics (ROC) were analyzed with SeHCAT as the gold standard. www.clinicaltrials.gov (NCT03059537).

Results: Patients with bile acid diarrhea (n = 26) had mean C4 of 30 ng/mL (95% confidence interval: 19-46) vs 8 (7-11; P < 0.001) in the miscellaneous diarrhea group (n = 45). Area under the ROC curve (ROCAUC) for C4 was 0.83 (0.72-0.93). C4 < 15 ng/mL had 85% (74%-96%) negative predictive value; C4 > 48 ng/mL had 82% (59%-100%) positive predictive value. Twenty patients had C4 values 15-48 ng/mL, of whom 11/20 had SeHCAT ≤10%. Median fasting FGF19 was 72 pg/mL (interquartile range: 53-146) vs 119 (84-240) (P = 0.004); ROCAUC was 0.71 (0.58-0.83). Stimulated FGF19 responses did not differ (P = 0.54).

Discussion: We identified C4 thresholds with clinically useful predictive values for the diagnosis of and screening for bile acid diarrhea in patients with chronic watery diarrhea. Further validation of the cutoff values with the placebo-controlled effect of sequestrant therapy is warranted (see Visual Abstract, Supplementary Digital Content 2, http://links.lww.com/AJG/B603).
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http://dx.doi.org/10.14309/ajg.0000000000000772DOI Listing
December 2020

Long-term consequences of one anastomosis gastric bypass on esogastric mucosa in a preclinical rat model.

Sci Rep 2020 04 30;10(1):7393. Epub 2020 Apr 30.

Inserm UMRS 1149, UFR de Médecine Paris Diderot, Université de Paris, AP-HP, Paris, France.

Although bariatric surgery is proven to sustain weight loss in morbidly obese patients, long-term adverse effects have yet to be fully characterized. This study compared the long-term consequences of two common forms of bariatric surgery: one-anastomosis gastric bypass (OAGB) and Roux-en-Y Gastric Bypass (RYGB) in a preclinical rat model. We evaluated the influence of biliopancreatic limb (BPL) length, malabsorption, and bile acid (BA) reflux on esogastric mucosa. After 30 weeks of follow-up, Wistar rats operated on RYGB, OAGB with a short BPL (15 cm, OAGB-15), or a long BPL (35 cm, OAGB-35), and unoperated rats exhibit no cases of esogastric cancer, metaplasia, dysplasia, or Barrett's esophagus. Compared to RYGB, OAGB-35 rats presented higher rate of esophagitis, fundic gastritis and perianastomotic foveolar hyperplasia. OAGB-35 rats also revealed the greatest weight loss and malabsorption. On the contrary, BA concentrations were the highest in the residual gastric pouch of OAGB-15 rats. Yet, no association could be established between the esogastric lesions and malabsorption, weight loss, or gastric bile acid concentrations. In conclusion, RYGB results in a better long-term outcome than OAGB, as chronic signs of biliary reflux or reactional gastritis were reported post-OAGB even after reducing the BPL length in a preclinical rat model.
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http://dx.doi.org/10.1038/s41598-020-64425-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7192900PMC
April 2020

Unraveling Host-Gut Microbiota Dialogue and Its Impact on Cholesterol Levels.

Front Pharmacol 2020 3;11:278. Epub 2020 Apr 3.

INSERM, UMRS U1166, "Integrative Biology of Atherosclerosis" and Sorbonne Université, Paris, France.

Disruption in cholesterol metabolism, particularly hypercholesterolemia, is a significant cause of atherosclerotic cardiovascular disease. Large interindividual variations in plasma cholesterol levels are traditionally related to genetic factors, and the remaining portion of their variance is accredited to environmental factors. In recent years, the essential role played by intestinal microbiota in human health and diseases has emerged. The gut microbiota is currently viewed as a fundamental regulator of host metabolism and of innate and adaptive immunity. Its bacterial composition but also the synthesis of multiple molecules resulting from bacterial metabolism vary according to diet, antibiotics, drugs used, and exposure to pollutants and infectious agents. Microbiota modifications induced by recent changes in the human environment thus seem to be a major factor in the current epidemic of metabolic/inflammatory diseases (diabetes mellitus, liver diseases, inflammatory bowel disease, obesity, and dyslipidemia). Epidemiological and preclinical studies report associations between bacterial communities and cholesterolemia. However, such an association remains poorly investigated and characterized. The objectives of this review are to present the current knowledge on and potential mechanisms underlying the host-microbiota dialogue for a better understanding of the contribution of microbial communities to the regulation of cholesterol homeostasis.
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http://dx.doi.org/10.3389/fphar.2020.00278DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7145900PMC
April 2020

Hepatoprotective impact of the bile acid receptor TGR5.

Liver Int 2020 05 30;40(5):1005-1015. Epub 2020 Mar 30.

INSERM U1193, Faculté des Sciences d'Orsay, Université Paris Saclay, Orsay, France.

During liver repair after injury, bile secretion has to be tightly modulated in order to preserve liver parenchyma from bile acid (BA)-induced injury. The mechanisms allowing the liver to maintain biliary homeostasis during repair after injury are not completely understood. Besides their historical role in lipid digestion, bile acids (BA) and their receptors constitute a signalling network with multiple impacts on liver repair, both stimulating regeneration and protecting the liver from BA overload. BA signal through nuclear (mainly Farnesoid X Receptor, FXR) and membrane (mainly G Protein-coupled BA Receptor 1, GPBAR-1 or TGR5) receptors to elicit a wide array of biological responses. While a great number of studies have been dedicated to the hepato-protective impact of FXR signalling, TGR5 is by far less explored in this context. Because the liver has to face massive and potentially harmful BA overload after partial ablation or destruction, BA-induced protective responses crucially contribute to spare liver repair capacities. Based on the available literature, the TGR5 BA receptor protects the remnant liver and maintains biliary homeostasis, mainly through the control of inflammation, biliary epithelial barrier permeability, BA pool hydrophobicity and sinusoidal blood flow. Mouse experimental models of liver injury reveal that in the lack of TGR5, excessive inflammation, leaky biliary epithelium and hydrophobic BA overload result in parenchymal insult and compromise optimal restoration of a functional liver mass. Translational perspectives are thus opened to target TGR5 with the aim of protecting the liver in the context of injury and BA overload.
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http://dx.doi.org/10.1111/liv.14427DOI Listing
May 2020

Intrahepatic Cholestasis Owing to a Novel Heterozygous ABCG8 Mutation and SLC4A2 Polymorphism With Favorable Outcome Under Ursodeoxycholic Acid.

Am J Gastroenterol 2019 09;114(9):1556-1559

Service d'hépato-gastroentérologie et nutrition, Hôpital Antoine-Béclère, Hôpitaux Universitaires Paris-Sud, Assistance Publique-Hôpitaux de Paris, Clamart, France.

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http://dx.doi.org/10.14309/ajg.0000000000000328DOI Listing
September 2019

Variations in gastrointestinal lipases, pH and bile acid levels with food intake, age and diseases: Possible impact on oral lipid-based drug delivery systems.

Adv Drug Deliv Rev 2019 03 26;142:3-15. Epub 2019 Mar 26.

Aix-Marseille Université, CNRS, UMR7281 Bioénergétique et Ingénierie des Protéines, 31 chemin Joseph Aiguier, 13402 Marseille cedex 09, France. Electronic address:

The lipids and some surfactants present in oral lipid-based drug delivery systems are potential substrates for the various lipases involved in gastrointestinal (GI) lipolysis. The levels of these enzymes, together with pH and biliairy secretion, are important parameters that condition the fate of lipid-based formulations (LBF) and the dispersion, solubilization and absorption of lipophilic drugs in the GI tract. Since in vitro methods of digestion are now combined with dissolution assays for a better assessment of LBF performance, it is essential to have a basic knowledge on lipase, pH and bile acid (BA) levels in vivo to develop relevant in vitro models. While these parameters and their variations in healthy subjects are today well documented, in vivo data on specific populations (age groups, patients with various diseases, patients with treatment affecting GI tract parameters, …) are scarce and obtaining them from clinical studies is sometimes difficult due to ethical limitations. Here we collected some in vivo data already available on the levels of digestive lipases, gastric and intestinal pH, and BAs at various ages and in patients with exocrine pancreatic insufficiency, a pathological situation that leads to drastic changes in GI tract parameters and impacts pharmacological treatments.
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http://dx.doi.org/10.1016/j.addr.2019.03.005DOI Listing
March 2019

CNCM I-745 Modulates the Fecal Bile Acids Metabolism During Antimicrobial Therapy in Healthy Volunteers.

Front Microbiol 2019 4;10:336. Epub 2019 Mar 4.

Inserm UMR1149, DHU Unity - Paris Diderot University, Paris, France.

CNCM I-745 (SB) is a probiotic yeast used to lower the incidence of antibiotic-associated () infection, though its mechanism of action remains unclear. Cholic acid is a primary bile acid, which triggers the germination and promotes the growth of . The intestinal microbiota transforms primary into secondary bile acids. This study examined (1) the antimicrobial-induced alteration of fecal bile acid content, and (2) whether the concomitant administration of SB influences this transformation. This is an ancillary work from a randomized study, which revealed that SB modulates fecal microbiota dysbiosis during antibiotic treatment. Healthy subjects were randomly assigned to (1) SB only, (2) amoxicillin-clavulanate (AC), (3) SB plus AC, or (4) no treatment. We analyzed fecal concentrations of BA by high performance liquid chromatography/tandem mass spectrometry. Compared to the untreated or the SB-treated groups, AC decreased the percentage of fecal secondary BA significantly (days 3 and 7). When SB and AC were administered concomitantly, this decrease in secondary BA was no longer significant. Following treatment with AC, a significant peak of fecal CA was measured on days 3 and 7, which was prevented by the concomitant administration of SB. AC administered to healthy volunteers altered the microbial transformation of primary BA, decreased secondary BA, and increased CA. The latter was prevented by the concomitant administration of SB and AC, suggesting a potent mechanism protection conferred by SB against post-antimicrobial infection. www.ClinicalTrials.gov, identifier NCT01473368.
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http://dx.doi.org/10.3389/fmicb.2019.00336DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6407479PMC
March 2019

TGR5-dependent hepatoprotection through the regulation of biliary epithelium barrier function.

Gut 2020 01 5;69(1):146-157. Epub 2019 Feb 5.

U1174, INSERM, Orsay, France.

Objective: We explored the hypothesis that TGR5, the bile acid (BA) G-protein-coupled receptor highly expressed in biliary epithelial cells, protects the liver against BA overload through the regulation of biliary epithelium permeability.

Design: Experiments were performed under basal and TGR5 agonist treatment. In vitro transepithelial electric resistance (TER) and FITC-dextran diffusion were measured in different cell lines. In vivo FITC-dextran was injected in the gallbladder (GB) lumen and traced in plasma. Tight junction proteins and TGR5-induced signalling were investigated in vitro and in vivo (wild-type [WT] and TGR5-KO livers and GB). WT and TGR5-KO mice were submitted to bile duct ligation or alpha-naphtylisothiocyanate intoxication under vehicle or TGR5 agonist treatment, and liver injury was studied.

Results: In vitro TGR5 stimulation increased TER and reduced paracellular permeability for dextran. In vivo dextran diffusion after GB injection was increased in TGR5-knock-out (KO) as compared with WT mice and decreased on TGR5 stimulation. In TGR5-KO bile ducts and GB, junctional adhesion molecule A (JAM-A) was hypophosphorylated and selectively downregulated among TJP analysed. TGR5 stimulation induced JAM-A phosphorylation and stabilisation both in vitro and in vivo, associated with protein kinase C-ζ activation. TGR5 agonist-induced TER increase as well as JAM-A protein stabilisation was dependent on JAM-A Ser285 phosphorylation. TGR5 agonist-treated mice were protected from cholestasis-induced liver injury, and this protection was significantly impaired in JAM-A-KO mice.

Conclusion: The BA receptor TGR5 regulates biliary epithelial barrier function in vitro and in vivo through an impact on JAM-A expression and phosphorylation, thereby protecting liver parenchyma against bile leakage.
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http://dx.doi.org/10.1136/gutjnl-2018-316975DOI Listing
January 2020

Predictive Value of Cellular Accumulation of Hydrophobic Bile Acids As a Marker of Cholestatic Drug Potential.

Toxicol Sci 2019 04;168(2):474-485

INSERM U1241, Numecan, Rennes, France.

Drug-induced cholestasis is mostly intrahepatic and characterized by alterations of bile canaliculi dynamics and morphology as well as accumulation of bile acids (BAs) in hepatocytes. However, little information exists on first changes in BA content and profile induced by cholestatic drugs in human liver. In this study, we aimed to analyze the effects of a large set of cholestatic and noncholestatic drugs in presence of physiological serum concentrations and 60-fold higher levels of 9 main BAs on cellular accumulation of BAs using HepaRG hepatocytes. BAs were measured in cell layers (cells + bile canaliculi) and culture media using high-pressure liquid chromatography coupled with tandem mass spectrometry after 24 h-treatment. Comparable changes in total and individual BA levels were observed in cell layers and media from control and noncholestatic drug-treated cultures: unconjugated BAs were actively amidated and lithocholic acid (LCA) was entirely sulfated. In contrast, cellular accumulation of LCA and in addition, of the 2 other hydrophobic BAs, chenodeoxycholic acid and deoxycholic acid, was evidenced only with cholestatic compounds in presence of BA mixtures at normal and 60-fold serum levels, respectively, suggesting that LCA was the first BA to accumulate. Cellular accumulation of hydrophobic BAs was associated with inhibition of their amidation and for LCA, its sulfation. In conclusion, these results demonstrated that cellular accumulation of unconjugated hydrophobic BAs can be caused by various cholestatic drugs in human hepatocytes and suggest that their cellular detection, especially that of LCA, could represent a new strategy for evaluation of cholestatic potential of drugs and other chemicals.
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http://dx.doi.org/10.1093/toxsci/kfz009DOI Listing
April 2019

Milk Polar Lipids in a High-Fat Diet Can Prevent Body Weight Gain: Modulated Abundance of Gut Bacteria in Relation with Fecal Loss of Specific Fatty Acids.

Mol Nutr Food Res 2019 02 25;63(4):e1801078. Epub 2019 Jan 25.

Univ Lyon, CarMeN Laboratory, INSERM U1060, INRA U1397, INSA Lyon, Université Claude Bernard Lyon 1, 69621, Villeurbanne, France.

Scope: Enhanced adiposity and metabolic inflammation are major features of obesity associated with altered gut microbiota and intestinal barrier. How these metabolic outcomes can be impacted by milk polar lipids (MPL), naturally containing 25% of sphingomyelin, is investigated in mice fed a mixed high-fat (HF) diet .

Methods And Results: Male C57Bl/6 mice receive a HF-diet devoid of MPL (21% fat, mainly palm oil, in chow), or supplemented with 1.1% or 1.6% of MPL (HF-MPL1; HF-MPL2) via a total-lipid extract from butterserum concentrate for 8 weeks. HF-MPL2 mice gain less weight versus HF (p < 0.01). Diets do not impact plasma markers of inflammation but in the liver, HF-MPL2 tends to decrease hepatic gene expression of macrophage marker F4/80 versus HF-MPL1 (p = 0.06). Colonic crypt depth is the maximum in HF-MPL2 (p < 0.05). In cecal microbiota, HF-MPL1 increases Bifidobacterium animalis versus HF (p < 0.05). HF-MPL2 decreases Lactobacillus reuteri (p < 0.05), which correlates negatively with the fecal loss of milk sphingomyelin-specific fatty acids (p < 0.05).

Conclusion: In mice fed a mixed HF diet, MPL can limit HF-induced body weight gain and modulate gut physiology and the abundance in microbiota of bacteria of metabolic interest. This supports further exploration of how residual unabsorbed lipids reaching the colon can impact HF-induced metabolic disorders.
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http://dx.doi.org/10.1002/mnfr.201801078DOI Listing
February 2019

Diet-Induced Dysbiosis and Genetic Background Synergize With Cystic Fibrosis Transmembrane Conductance Regulator Deficiency to Promote Cholangiopathy in Mice.

Hepatol Commun 2018 Dec 10;2(12):1533-1549. Epub 2018 Oct 10.

Sorbonne Université, INSERM Centre de Recherche Saint-Antoine (CRSA), and Institute of Cardiometabolism and Nutrition (ICAN) Paris France.

The most typical expression of cystic fibrosis (CF)-related liver disease is a cholangiopathy that can progress to cirrhosis. We aimed to determine the potential impact of environmental and genetic factors on the development of CF-related cholangiopathy in mice. Cystic fibrosis transmembrane conductance regulator () mice and littermates in a congenic C57BL/6J background were fed a high medium-chain triglyceride (MCT) diet. Liver histopathology, fecal microbiota, intestinal inflammation and barrier function, bile acid homeostasis, and liver transcriptome were analyzed in 3-month-old males. Subsequently, MCT diet was changed for chow with polyethylene glycol (PEG) and the genetic background for a mixed C57BL/6J;129/Ola background (resulting from three backcrosses), to test their effect on phenotype. C57BL/6J mice on an MCT diet developed cholangiopathy features that were associated with dysbiosis, primarily enrichment, and low-grade intestinal inflammation. Compared with littermates, they displayed increased intestinal permeability and a lack of secondary bile acids together with a low expression of ileal bile acid transporters. Dietary-induced (chow with PEG) changes in gut microbiota composition largely prevented the development of cholangiopathy in mice. Regardless of status, mice in a mixed C57BL/6J;129/Ola background developed fatty liver under an MCT diet. The mice in the mixed background showed no cholangiopathy, which was not explained by a difference in gut microbiota or intestinal permeability, compared with congenic mice. Transcriptomic analysis of the liver revealed differential expression, notably of immune-related genes, in mice of the congenic versus mixed background. , our findings suggest that CFTR deficiency causes abnormal intestinal permeability, which, combined with diet-induced dysbiosis and immune-related genetic susceptibility, promotes CF-related cholangiopathy.
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http://dx.doi.org/10.1002/hep4.1266DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6287479PMC
December 2018

Inhibitory Effect of Ursodeoxycholic Acid on Germination Is Insufficient to Prevent Colitis: A Study in Hamsters and Humans.

Front Microbiol 2018 22;9:2849. Epub 2018 Nov 22.

INSERM U1149, Centre de Recherche sur l'Inflammation, Faculté de Médecine Paris Diderot, Université Paris Diderot, Paris, France.

Bile acids (BA) influence germination and growth of . Ursodeoxycholic acid (UDCA), a BA minor in human, used for cholestatic liver diseases, inhibits germination and growth of , but was never tested with an infectious challenge versus control. We hypothesized that UDCA could prevent CDI. We evaluated the effects of UDCA on and in hamsters, with pharmacokinetics study and with an infectious challenge. Then, we studied CDI incidence in UDCA-treated patients. We evaluated germination and growth of , with 0.01, 0.05, and 0.1% UDCA. We analyzed fecal BA of hamsters receiving antibiotics and UDCA (50 mg/kg/day), antibiotics, or UDCA alone. Then, we challenged with spores of at D6 hamsters treated with UDCA (50 mg/kg/day) from D1 to D13, versus control. In human, we analyzed the database of a cohort on CDI in acute flares of inflammatory bowel disease (IBD). As PSC-IBD patients were under UDCA treatment, we compared PSC-IBD patients to IBD patients without PSC. , UDCA inhibited germination and growth of at 0.05 and 0.1%, competing with 0.1% TCA (with 0.1%: 0.05% ± 0.05% colony forming unit versus 100% ± 0%, < 0.0001). In hamsters, UDCA reached high levels only when administered with antibiotics (43.5% UDCA at D5). Without antibiotics, UDCA was in small amount in feces (max. 4.28%), probably because of UDCA transformation into LCA by gut microbiota. During infectious challenge, mortality was similar in animals treated or not with UDCA (62.5%, = 5/8, = 0.78). UDCA percentage was high, similar and with the same kinetics in dead and surviving hamsters. However, dead hamsters had a higher ratio of primary over secondary BA compared to surviving hamsters. 9% ( = 41/404) of IBD patients without PSC had a CDI, versus 25% ( = 4/12) of PSC-IBD patients treated with UDCA. We confirmed the inhibitory effect of UDCA on growth and germination of , with 0.05 or 0.1% UDCA. However, in our hamster model, UDCA was inefficient to prevent CDI, despite high levels of UDCA in feces. Patients with PSC-IBD treated with UDCA did not have less CDI than IBD patients.
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http://dx.doi.org/10.3389/fmicb.2018.02849DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6262072PMC
November 2018

Antipruritic effect of bezafibrate and serum autotaxin measures in patients with primary biliary cholangitis.

Gut 2019 10 18;68(10):1902-1903. Epub 2018 Sep 18.

Reference Center for Inflammatory Biliary Diseases and Autoimmune Hepatitis, Saint-Antoine Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Paris, France.

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http://dx.doi.org/10.1136/gutjnl-2018-317426DOI Listing
October 2019

Postprandial bile acid levels in intestine and plasma reveal altered biliary circulation in chronic pancreatitis patients.

J Lipid Res 2018 11 11;59(11):2202-2213. Epub 2018 Sep 11.

CNRS, Aix-Marseille Université, UMR 7281 Bioénergétique et Ingénerie des Protéines, Marseille, France

Bile acid (BA) secretion and circulation in chronic pancreatitis (CP) patients with exocrine pancreatic insufficiency (EPI) were investigated by simultaneously measuring postprandial levels of individual BAs in duodenal contents and blood plasma using LC-MS/MS. CP patients and healthy volunteers (HVs) were intubated with gastric and duodenal tubes prior to the administration of a test meal and continuous aspiration of duodenal contents. Pancreatic lipase outputs in CP patients were very low (0.7 ± 0.2 mg) versus HVs (116.7 ± 68.1 mg; < 0.005), thus confirming the severity of EPI. Duodenal BA outputs were reduced in CP patients (1.00 ± 0.89 mmol; 0.47 ± 0.42 g) versus HVs (5.52 ± 4.53 mmol; 2.62 ± 2.14 g; < 0.15). Primary to secondary BA ratio was considerably higher in CP patients (38.09 ± 48.1) than HVs (4.15 ± 2.37; < 0.15), indicating an impaired transformation of BAs by gut microbiota. BA concentrations were found below the critical micellar concentration in CP patients, while a high BA concentration peak corresponding to gallbladder emptying was evidenced in HVs. Conversely, BA plasma concentration was increased in CP patients versus HVs suggesting a cholangiohepatic shunt of BA secretion. Alterations of BA circulation and levels may result from the main biliary duct stenosis observed in these CP patients and may aggravate the consequences of EPI on lipid malabsorption.
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http://dx.doi.org/10.1194/jlr.M084830DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6210915PMC
November 2018

Inter-kingdom effect on epithelial cells of the N-Acyl homoserine lactone 3-oxo-C12:2, a major quorum-sensing molecule from gut microbiota.

PLoS One 2018 29;13(8):e0202587. Epub 2018 Aug 29.

Sorbonne Université, École normale supérieure, PSL University, CNRS, INSERM, APHP, Hôpital Saint-Antoine, Laboratoire des biomolécules, LBM, Paris, France.

Background And Aims: N-acyl homoserine lactones (AHLs), which are autoinducer quorum-sensing molecules involved in the bacterial communication network, also interact with eukaryotic cells. Searching for these molecules in the context of inflammatory bowel disease (IBD) is appealing. The aims of our study were to look for AHL molecules in faecal samples from healthy subjects (HS) and IBD patients to correlate AHL profiles with the microbiome and investigate the effect of AHLs of interest on epithelial cells.

Methods: Using mass spectrometry, we characterised AHL profiles in faecal samples from HS (n = 26) and IBD patients in remission (n = 24) and in flare (n = 25) and correlated the presence of AHLs of interest with gut microbiota composition obtained by real-time qPCR and 16S sequencing. We synthesised AHLs of interest to test the inflammatory response after IL1β stimulation and paracellular permeability on Caco-2 cells.

Results: We observed 14 different AHLs, among which one was prominent. This AHL corresponded to 3-oxo-C12:2 and was found significantly less frequently in IBD patients in flare (16%) and in remission (37.5%) versus HS (65.4%) (p = 0.001). The presence of 3-oxo-C12:2 was associated with significantly higher counts of Firmicutes, especially Faecalbacterium prausnitzii, and lower counts of Escherichia coli. In vitro, 3-oxo-C12:2 exerted an anti-inflammatory effect on Caco-2 cells. Interestingly, although 3-oxo-C12, the well-known AHL from Pseudomonas aeruginosa, increased paracellular permeability, 3-oxo-C12:2 did not.

Conclusions: We identified AHLs in the human gut microbiota and discovered a new and prominent AHL, 3-oxo-C12:2, which correlates with normobiosis and exerts a protective effect on gut epithelial cells.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0202587PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6114859PMC
February 2019

Bile acid homeostasis and intestinal dysbiosis in alcoholic hepatitis.

Aliment Pharmacol Ther 2018 11 24;48(9):961-974. Epub 2018 Aug 24.

Inflammation Chimiokines et Immunopathologie, DHU Hepatinov, Faculté de Médecine-Université Paris-Sud/Université Paris-Saclay, INSERM, UMR-S 996, Clamart, France.

Background: Intestinal microbiota plays an important role in bile acid homeostasis.

Aim: To study the structure of the intestinal microbiota and its function in bile acid homeostasis in alcoholic patients based on the severity of alcoholic liver disease.

Methods: In this prospective study, we included four groups of active alcoholic patients (N = 108): two noncirrhotic, with (noCir_AH, n = 13) or without alcoholic hepatitis (noCir_noAH, n = 61), and two cirrhotic, with (Cir_sAH, n = 17) or without severe alcoholic hepatitis (Cir_noAH, n = 17). Plasma and faecal bile acid profiles and intestinal microbiota composition were assessed.

Results: Plasma levels of total bile acids (84.6 vs 6.8 μmol/L, P < 0.001) and total ursodeoxycholic acid (1.3 vs 0.3 μmol/L, P = 0.03) were higher in cirrhosis with severe alcoholic hepatitis (Cir_sAH) than Cir_noAH, whereas total faecal (2.4 vs 11.3, P = 0.01) and secondary bile acids (0.7 vs 10.7, P < 0.01) levels were lower. Cir_sAH patients had a different microbiota than Cir_noAH patients: at the phyla level, the abundance of Actinobacteria (9 vs 1%, P = 0.01) was higher and that of Bacteroidetes was lower (25 vs 40%, P = 0.04). Moreover, the microbiota of Cir_sAH patients showed changes in the abundance of genes involved in 15 metabolic pathways, including upregulation of glutathione metabolism, and downregulation of biotin metabolism.

Conclusions: Patients with Cir_sAH show specific changes of the bile acid pool with a shift towards more hydrophobic and toxic species that may be responsible for the specific microbiota changes. Conversely, the microbiota may also alter the bile acid pool by transforming primary to secondary bile acids, leading to a vicious cycle.
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http://dx.doi.org/10.1111/apt.14949DOI Listing
November 2018

Bilophila wadsworthia aggravates high fat diet induced metabolic dysfunctions in mice.

Nat Commun 2018 07 18;9(1):2802. Epub 2018 Jul 18.

Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.

Dietary lipids favor the growth of the pathobiont Bilophila wadsworthia, but the relevance of this expansion in metabolic syndrome pathogenesis is poorly understood. Here, we showed that B. wadsworthia synergizes with high fat diet (HFD) to promote higher inflammation, intestinal barrier dysfunction and bile acid dysmetabolism, leading to higher glucose dysmetabolism and hepatic steatosis. Host-microbiota transcriptomics analysis reveal pathways, particularly butanoate metabolism, which may underlie the metabolic effects mediated by B. wadsworthia. Pharmacological suppression of B. wadsworthia-associated inflammation demonstrate the bacterium's intrinsic capacity to induce a negative impact on glycemic control and hepatic function. Administration of the probiotic Lactobacillus rhamnosus CNCM I-3690 limits B. wadsworthia-induced immune and metabolic impairment by limiting its expansion, reducing inflammation and reinforcing intestinal barrier. Our results suggest a new avenue for interventions against western diet-driven inflammatory and metabolic diseases.
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http://dx.doi.org/10.1038/s41467-018-05249-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6052103PMC
July 2018

A Placebo-Controlled Trial of Bezafibrate in Primary Biliary Cholangitis.

N Engl J Med 2018 Jun;378(23):2171-2181

From the Reference Center for Inflammatory Biliary Diseases and Autoimmune Hepatitis, Hepatology and Gastroenterology Department, Saint-Antoine University Hospital, Assistance Publique-Hôpitaux de Paris (APHP) (C.C., O.C., S.L., F.G., R.P.), INSERM Unité Mixte de Recherche (UMR) S938 (C.C., O.C., S.L., R.P.) and the Biochemistry Laboratory (L.H., D.R.), Saint-Antoine University Hospital, APHP, INSERM Unité 1157/UMR 7203, Sorbonne University, the Biochemistry Laboratory, Tenon University Hospital, APHP (G.L.), and the Immunology Laboratory, INSERM UMR S996, Bichat University Hospital, APHP (L.C., S.C.-M.), Paris-Sud University, the Department of Clinical Pharmacology and Clinical Research Platform of the East of Paris, APHP (A.R., F.-H.A., T.S.), and Sorbonne University (T.S.), Paris, the Hepatology and Gastroenterology Department, Rouen University Hospital, Rouen (O.G.), the Hepatology and Gastroenterology Department, Pontchaillou University Hospital, Rennes (A.L.G.), the Hepatology and Gastroenterology Department, University Hospitals of Strasbourg, Institute of Viral and Liver Diseases, INSERM Unité 1110, Laboratory of Excellence HepSYS, University of Strasbourg, Strasbourg (F.H.), the Hepatology and Gastroenterology Department, Claude Huriez University Hospital, Lille (P.M.), the Hepatology and Gastroenterology Department, Orleans Hospital, Orleans (P.P.), the Hepatology and Gastroenterology Department, Dijon Bourgogne University Hospital, Dijon (A.M.), the Hepatology and Gastroenterology Department, University Hospital of Poitiers, Poitiers (C.S.), the Hepatology and Gastroenterology Department, Estaing University Hospital, Clermont-Ferrand (A.A.), the Hepatology and Gastroenterology Department, University Hospital of Limoges, Limoges (M.D.-G.), the Hepatology and Gastroenterology Department, Saint-Eloi University Hospital, Montpellier (D.L.), the Hepatology Department, Beaujon University Hospital, Clichy (O.R.), the Hepatology and Gastroenterology Department, Brabois University Hospital, Nancy (J.-P.B.), the Hepatology and Gastroenterology Department, University Hospital of Angers, Hemodynamics, Interaction, Fibrosis, and Tumor Invasiveness in Hepatic and Digestive Organs Laboratory, Unité Propre de Recherche de l'Enseignement Supérieur 3859, Structures Fédératives de Recherche 4208, Bretagne Loire University, Angers (J.B.), the Hepatology and Gastroenterology Department, Haut-Lévêque University Hospital, Pessac (V.L.), the Hepatology and Gastroenterology Department, Robert Debré University Hospital, Reims (A.H.-B.), the Hepatology and Gastroenterology Department, University Hospital of Amiens, Amiens (E.N.-K.), the Hepatology and Gastroenterology Department, Croix-Rousse University Hospital, Lyon (F.Z.), the Hepatology and Gastroenterology Department, University Hospital of Caen, Caen (I.O.-H.), the Hepatology and Gastroenterology Department, Michallon University Hospital, Grenoble (J.-P.Z.), and the Hepatology and Gastroenterology Department, Jean Verdier University Hospital, Bondy (G.N.) - all in France.

Background: Patients with primary biliary cholangitis who have an inadequate response to therapy with ursodeoxycholic acid are at high risk for disease progression. Fibrates, which are agonists of peroxisome proliferator-activated receptors, in combination with ursodeoxycholic acid, have shown potential benefit in patients with this condition.

Methods: In this 24-month, double-blind, placebo-controlled, phase 3 trial, we randomly assigned 100 patients who had had an inadequate response to ursodeoxycholic acid according to the Paris 2 criteria to receive bezafibrate at a daily dose of 400 mg (50 patients), or placebo (50 patients), in addition to continued treatment with ursodeoxycholic acid. The primary outcome was a complete biochemical response, which was defined as normal levels of total bilirubin, alkaline phosphatase, aminotransferases, and albumin, as well as a normal prothrombin index (a derived measure of prothrombin time), at 24 months.

Results: The primary outcome occurred in 31% of the patients assigned to bezafibrate and in 0% assigned to placebo (difference, 31 percentage points; 95% confidence interval, 10 to 50; P<0.001). Normal levels of alkaline phosphatase were observed in 67% of the patients in the bezafibrate group and in 2% in the placebo group. Results regarding changes in pruritus, fatigue, and noninvasive measures of liver fibrosis, including liver stiffness and Enhanced Liver Fibrosis score, were consistent with the results of the primary outcome. Two patients in each group had complications from end-stage liver disease. The creatinine level increased 5% from baseline in the bezafibrate group and decreased 3% in the placebo group. Myalgia occurred in 20% of the patients in the bezafibrate group and in 10% in the placebo group.

Conclusions: Among patients with primary biliary cholangitis who had had an inadequate response to ursodeoxycholic acid alone, treatment with bezafibrate in addition to ursodeoxycholic acid resulted in a rate of complete biochemical response that was significantly higher than the rate with placebo and ursodeoxycholic acid therapy. (Funded by Programme Hospitalier de Recherche Clinique and Arrow Génériques; BEZURSO ClinicalTrials.gov number, NCT01654731 .).
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http://dx.doi.org/10.1056/NEJMoa1714519DOI Listing
June 2018

Roux-en-Y Gastric-Bypass and sleeve gastrectomy induces specific shifts of the gut microbiota without altering the metabolism of bile acids in the intestinal lumen.

Int J Obes (Lond) 2019 02 30;43(2):428-431. Epub 2018 Jan 30.

Sorbonne Universités, UPMC Univ. Paris 06, École normale supérieure, PSL Research University, CNRS, INSERM, APHP, Laboratoire des Biomolécules (LBM), 27 rue de Chaligny, Paris, 75005, France.

Some shifts in the gut microbiota composition and its metabolic fingerprints have been associated to Sleeve gastrectomy (SG) and Roux-en-Y Gastric Bypass (RYGB). So far, plasma bile acids have been associated with post-operative glucose improvement and weight loss, but nothing is known about their metabolism in the gut lumen. As bile acids are physiologically transformed by the microbiota into various species, the aim of this work was to study how SG and RYGB-associated dysbiosis impact the bioconversion of bile acids in the intestinal lumen. Comparing SHAM (n = 9) with our validated rat models of SG (n = 5) and RYGB (n = 6), we quantified luminal bile acids along the gut and found that the metabolic transformation of bile acids (deconjugation, dehydroxylation, and epimerization) is not different from the duodenum to the colon. However, in the cecum where the biotransformation mainly takes place, we observed deep alterations of the microbiota composition, which were specific of each type of surgery. In conclusion, despite specific dysbiosis after surgery, the bile acids metabolism in the gut lumen is highly preserved, suggesting that a resilience of the gut microbiota occurs after these procedures.
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http://dx.doi.org/10.1038/s41366-018-0015-3DOI Listing
February 2019

Plasma oxysterols: biomarkers for diagnosis and treatment in spastic paraplegia type 5.

Brain 2018 01;141(1):72-84

APHP, La Pitié-Salpêtrière University Hospital, Reference Center for Adult Neurometabolic Diseases, Paris, France.

The hereditary spastic paraplegias are an expanding and heterogeneous group of disorders characterized by spasticity in the lower limbs. Plasma biomarkers are needed to guide the genetic testing of spastic paraplegia. Spastic paraplegia type 5 (SPG5) is an autosomal recessive spastic paraplegia due to mutations in CYP7B1, which encodes a cytochrome P450 7α-hydroxylase implicated in cholesterol and bile acids metabolism. We developed a method based on ultra-performance liquid chromatography electrospray tandem mass spectrometry to validate two plasma 25-hydroxycholesterol (25-OHC) and 27-hydroxycholesterol (27-OHC) as diagnostic biomarkers in a cohort of 21 patients with SPG5. For 14 patients, SPG5 was initially suspected on the basis of genetic analysis, and then confirmed by increased plasma 25-OHC, 27-OHC and their ratio to total cholesterol. For seven patients, the diagnosis was initially based on elevated plasma oxysterol levels and confirmed by the identification of two causal CYP7B1 mutations. The receiver operating characteristic curves analysis showed that 25-OHC, 27-OHC and their ratio to total cholesterol discriminated between SPG5 patients and healthy controls with 100% sensitivity and specificity. Taking advantage of the robustness of these plasma oxysterols, we then conducted a phase II therapeutic trial in 12 patients and tested whether candidate molecules (atorvastatin, chenodeoxycholic acid and resveratrol) can lower plasma oxysterols and improve bile acids profile. The trial consisted of a three-period, three-treatment crossover study and the six different sequences of three treatments were randomized. Using a linear mixed effect regression model with a random intercept, we observed that atorvastatin decreased moderately plasma 27-OHC (∼30%, P < 0.001) but did not change 27-OHC to total cholesterol ratio or 25-OHC levels. We also found an abnormal bile acids profile in SPG5 patients, with significantly decreased total serum bile acids associated with a relative decrease of ursodeoxycholic and lithocholic acids compared to deoxycholic acid. Treatment with chenodeoxycholic acid restored bile acids profile in SPG5 patients. Therefore, the combination of atorvastatin and chenodeoxycholic acid may be worth considering for the treatment of SPG5 patients but the neurological benefit of these metabolic interventions remains to be evaluated in phase III therapeutic trials using clinical, imaging and/or electrophysiological outcome measures with sufficient effect sizes. Overall, our study indicates that plasma 25-OHC and 27-OHC are robust diagnostic biomarkers of SPG5 and shall be used as first-line investigations in any patient with unexplained spastic paraplegia.
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http://dx.doi.org/10.1093/brain/awx297DOI Listing
January 2018

Progressive and Preferential Cellular Accumulation of Hydrophobic Bile Acids Induced by Cholestatic Drugs Is Associated with Inhibition of Their Amidation and Sulfation.

Drug Metab Dispos 2017 12 19;45(12):1292-1303. Epub 2017 Sep 19.

INSERM UMR991/1241, Liver Metabolism and Cancer/Numecan, Rennes, France (A.S., A.B., C.G.-G., A.G.); Université de Rennes 1, Rennes, France (A.S., A.B., C.G.-G., A.G.); and ERL INSERM U1157/UMR7203, Faculté de Médecine Pierre et Marie Curie, Site Saint Antoine, Paris, France (L.H., D.R.)

Drug-induced intrahepatic cholestasis is characterized by cellular accumulation of bile acids (BAs), whose mechanisms remain poorly understood. The present study aimed to analyze early and progressive alterations of BA profiles induced by cyclosporine A, chlorpromazine, troglitazone, tolcapone, trovafloxacin, and tacrolimus after 4-hour, 24-hour, and 6-day treatments of differentiated HepaRG cells. In BA-free medium, the potent cholestatic drugs cyclosporine A, chlorpromazine, and troglitazone reduced endogenous BA synthesis after 24 hours, whereas the rarely cholestatic drugs tolcapone, trovafloxacin, and tacrolimus reduced BA synthesis only after 6 days. In the presence of physiologic serum BA concentrations, cyclosporine A, chlorpromazine, and troglitazone induced early and preferential cellular accumulation of unconjugated lithocholic, deoxycholic, and chenodeoxycholic acids that increased 8- to 12-fold and 47- to 50-fold after 24 hours and 6 days, respectively. Accumulation of these hydrophobic BAs resulted from strong inhibition of amidation, and in addition, for lithocholic acid reduction of its sulfoconjugation, and was associated with variable alterations of uptake and efflux transporters. Trovafloxacin also caused BA accumulation, especially after 6 days, whereas tolcapone and tacrolimus were still without effect. However, when exogenous BAs were added to the medium at cholestatic serum concentrations, a 6-day treatment with all drugs resulted in cellular BA accumulation with higher folds of chenodeoxycholic and lithocholic acids. At the tested concentration, tolcapone had the lowest effect. These results bring the first demonstration that major cholestatic drugs can cause preferential and progressive in vitro cellular accumulation of unconjugated toxic hydrophobic BAs and bring new insights into mechanisms involved in drug-induced cellular accumulation of toxic BAs.
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http://dx.doi.org/10.1124/dmd.117.077420DOI Listing
December 2017

Glycerolipid analysis during desiccation and recovery of the resurrection plant Xerophyta humilis (Bak) Dur and Schinz.

Plant Cell Environ 2018 03 10;41(3):533-547. Epub 2017 Nov 10.

Université Paris-Est, UPEC, Institut d'Ecologie et des Sciences Environnementales de Paris, 94010, Créteil Cedex, France.

Xerophyta humilis is a poikilochlorophyllous monocot resurrection plant used as a model to study vegetative desiccation tolerance. Dehydration imposes tension and ultimate loss of integrity of membranes in desiccation sensitive species. We investigated the predominant molecular species of glycerolipids present in root and leaf tissues, using multiple reaction monitoring mass spectrometry, and then analysed changes therein during dehydration and subsequent rehydration of whole plants. The presence of fatty acids with long carbon chains and with odd numbers of carbons were detected and confirmed by gas chromatography. Dehydration of both leaves and roots resulted in an increase in species containing polyunsaturated fatty acids and a decrease in disaturated species. Upon rehydration, lipid saturation was reversed, with this being initiated immediately upon watering in roots but only 12-24 hr later in leaves. Relative levels of species with short-chained odd-numbered saturated fatty acids decreased during dehydration and increased during rehydration, whereas the reverse trend was observed for long-chained fatty acids. X. humilis has a unique lipid composition, this report being one of the few to demonstrate the presence of odd-numbered fatty acids in plant phosphoglycerolipids.
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http://dx.doi.org/10.1111/pce.13063DOI Listing
March 2018

Bile acids and their receptors during liver regeneration: "Dangerous protectors".

Mol Aspects Med 2017 08 23;56:25-33. Epub 2017 Mar 23.

INSERM U.1174, Université Paris Sud, bât. 443, 91405 Orsay, France; Université Paris Sud, bât. 443, 91405 Orsay, France. Electronic address:

Tissue repair is orchestrated by a finely tuned interplay between processes of regeneration, inflammation and cell protection, allowing organisms to restore their integrity after partial loss of cells or organs. An important, although largely unexplored feature is that after injury and during liver repair, liver functions have to be maintained to fulfill the peripheral demand. This is particularly critical for bile secretion, which has to be finely modulated in order to preserve liver parenchyma from bile-induced injury. However, mechanisms allowing the liver to maintain biliary homeostasis during repair after injury are not completely understood. Besides cytokines and growth factors, bile acids (BA) and their receptors constitute an insufficiently explored signaling network during liver regeneration and repair. BA signal through both nuclear (mainly Farnesoid X Receptor, FXR) and membrane (mainly G Protein-coupled BA Receptor 1, GPBAR-1 or TGR5) receptors which distributions are large in the organism, and which activation elicits a wide array of biological responses. While a number of studies have been dedicated to FXR signaling in liver repair processes, TGR5 remains poorly explored in this context. Because of the massive and potentially harmful BA overload that faces the remnant liver after partial ablation or destruction, both BA-induced adaptive and proliferative responses may stand in a central position to contribute to the regenerative response. Based on the available literature, both BA receptors may act in synergy during the regeneration process, in order to protect the remnant liver and maintain biliary homeostasis, otherwise potentially toxic BA overload would result in parenchymal insult and compromise optimal restoration of a functional liver mass.
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http://dx.doi.org/10.1016/j.mam.2017.03.002DOI Listing
August 2017

Long-Term Evaluation of Biliary Reflux After Experimental One-Anastomosis Gastric Bypass in Rats.

Obes Surg 2017 04;27(4):1119-1122

Service de Chirurgie Digestive, AP-HP Hôpital Européen Georges Pompidou, 75015, Paris, France.

Background: Controversy remains regarding biliary reflux after one-anastomosis gastric bypass (OAGB). The aim of this "pilot" study was to analyze biliary reflux and its potential long-term consequences on esogastric mucosae in OAGB-operated rats.

Methods: Diet-induced obese rats were subjected to OAGB (n = 10) or sham (n = 4) surgery and followed up for 16 weeks. Evolution of weight and glucose tolerance was analyzed. Bile acid concentration measurement, histological and qRT-PCR analysis were performed in the esogastric segments.

Results: Weight loss and glucose tolerance were improved after OAGB. Mean bile acid concentration was 4.2 times higher in the esogastric segments of OAGB rats (compared to sham). A foveolar hyperplasia of the gastro-jejunal anastomosis and an eosinophilic polynuclear cell infiltration were observed in OAGB rats. An esophageal hyper-papillomatosis was observed in both groups (OAGB = 50%, sham = 50%). qRT-PCR analysis showed no differences between OAGB and sham mRNA levels of Barrett's esophagus or esogastric carcinogenic-specific genes. No intestinal metaplasia, dysplasia, or cancer were observed after a 16-week follow-up.

Conclusions: After a 16-week follow-up, this pilot study confirmed the good reproducibility of our OAGB rat model. OAGB rats had not developed any pre-cancerous or cancerous lesions. Further experimental studies with longer term follow-up are required.
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http://dx.doi.org/10.1007/s11695-017-2577-xDOI Listing
April 2017

Fecal microbiota manipulation prevents dysbiosis and alcohol-induced liver injury in mice.

J Hepatol 2017 04 25;66(4):806-815. Epub 2016 Nov 25.

INSERM U996, DHU Hepatinov, Univ Paris-Sud, Université Paris-Saclay, 92140 Clamart, France; Institut Paris-Sud d'Innovation Thérapeutique (IPSIT), IFR141, Faculté de Pharmacie, Univ Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France. Electronic address:

Background & Aims: Alcoholic liver disease (ALD) is a leading cause of liver failure and mortality. In humans, severe alcoholic hepatitis is associated with key changes to intestinal microbiota (IM), which influences individual sensitivity to develop advanced ALD. We used the different susceptibility to ALD observed in two distinct animal facilities to test the efficiency of two complementary strategies (fecal microbiota transplantation and prebiotic treatment) to reverse dysbiosis and prevent ALD.

Methods: Mice were fed alcohol in two distinct animal facilities with a Lieber DeCarli diet. Fecal microbiota transplantation was performed with fresh feces from alcohol-resistant donor mice to alcohol-sensitive receiver mice three times a week. Another group of mice received pectin during the entire alcohol consumption period.

Results: Ethanol induced steatosis and liver inflammation, which were associated with disruption of gut homeostasis, in alcohol-sensitive, but not alcohol resistant mice. IM analysis showed that the proportion of Bacteroides was specifically lower in alcohol-sensitive mice (p<0.05). Principal coordinate analysis showed that the IM of sensitive and resistant mice clustered differently. We targeted IM using two different strategies to prevent alcohol-induced liver lesions: (1) pectin treatment which induced major modifications of the IM, (2) fecal microbiota transplantation which resulted in an IM very close to that of resistant donor mice in the sensitive recipient mice. Both methods prevented steatosis, liver inflammation, and restored gut homeostasis.

Conclusions: Manipulation of IM can prevent alcohol-induced liver injury. The IM should be considered as a new therapeutic target in ALD.

Lay Summary: Sensitivity to alcoholic liver disease (ALD) is driven by intestinal microbiota in alcohol fed mice. Treatment of mice with alcohol-induced liver lesions by fecal transplant from alcohol fed mice resistant to ALD or with prebiotic (pectin) prevents ALD. These findings open new possibilities for treatment of human ALD through intestinal microbiota manipulation.
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http://dx.doi.org/10.1016/j.jhep.2016.11.008DOI Listing
April 2017

Lysophosphatidylcholine acyltransferase 1 is downregulated by hepatitis C virus: impact on production of lipo-viro-particles.

Gut 2017 12 31;66(12):2160-2169. Epub 2016 Aug 31.

Université Paris Descartes, EA 4474 «Hepatitis C Virology», Paris, France.

Objective: HCV is intimately linked with the liver lipid metabolism, devoted to the efflux of triacylglycerols stored in lipid droplets (LDs) in the form of triacylglycerol-rich very-low-density lipoproteins (VLDLs): (i) the most infectious HCV particles are those of lowest density due to association with triacylglycerol-rich lipoproteins and (ii) HCV-infected patients frequently develop hepatic steatosis (increased triacylglycerol storage). The recent identification of lysophosphatidylcholine acyltransferase 1 (LPCAT1) as an LD phospholipid-remodelling enzyme prompted us to investigate its role in liver lipid metabolism and HCV infectious cycle.

Design: Huh-7.5.1 cells and primary human hepatocytes (PHHs) were infected with JFH1-HCV. LPCAT1 depletion was achieved by RNA interference. Cells were monitored for LPCAT1 expression, lipid metabolism and HCV production and infectivity. The density of viral particles was assessed by isopycnic ultracentrifugation.

Results: Upon HCV infection, both Huh-7.5.1 cells and PHH had decreased levels of LPCAT1 transcript and protein, consistent with transcriptional downregulation. LPCAT1 depletion in either naive or infected Huh-7.5.1 cells resulted in altered lipid metabolism characterised by LD remodelling, increased triacylglycerol storage and increased secretion of VLDL. In infected Huh-7.5.1 cells or PHH, LPCAT1 depletion increased production of the viral particles of lowest density and highest infectivity.

Conclusions: We have identified LPCAT1 as a modulator of liver lipid metabolism downregulated by HCV, which appears as a viral strategy to increase the triacylglycerol content and hence infectivity of viral particles. Targeting this metabolic pathway may represent an attractive therapeutic approach to reduce both the viral titre and hepatic steatosis.
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http://dx.doi.org/10.1136/gutjnl-2016-311508DOI Listing
December 2017

The P2X4 purinergic receptor impacts liver regeneration after partial hepatectomy in mice through the regulation of biliary homeostasis.

Hepatology 2016 09 15;64(3):941-53. Epub 2016 Jul 15.

INSERM U1174, Université Paris Sud, Orsay, France.

Unlabelled: Many regulatory pathways are involved in liver regeneration after partial hepatectomy (PH), to initiate growth, protect liver cells, and sustain remnant liver functions. Extracellular adenosine triphosphate rises in blood and bile after PH and contributes to liver regeneration, although purinergic receptors and mechanisms remain to be precisely explored. In this work we analyzed during regeneration after PH the involvement of P2X4 purinergic receptors, highly expressed in the liver. P2X4 receptor expression in the liver, liver histology, hepatocyte proliferation, plasma bile acid concentration, bile flow and composition, and lysosome distribution in hepatocytes were studied in wild-type and P2X4 knockout (KO) mice, before and after PH. P2X4 receptors were expressed in hepatocytes and Kupffer cells; in hepatocytes, P2X4 was concentrated in subcanalicular areas closely costained with lysosomal markers. After PH, delayed regeneration, hepatocyte necrosis, and cholestasis were observed in P2X4-KO mice. In P2X4-KO mice, post-PH biliary adaptation was impaired with a smaller increase in bile flow and HCO3 (-) biliary output, as well as altered biliary composition with reduced adenosine triphosphate and lysosomal enzyme release. In line with these data, lysosome distribution and biogenesis were altered in P2X4-KO compared with wild-type mice.

Conclusion: During liver regeneration after PH, P2X4 contributes to the complex control of biliary homeostasis through mechanisms involving pericanalicular lysosomes, with a resulting impact on hepatocyte protection and proliferation. (Hepatology 2016;64:941-953).
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http://dx.doi.org/10.1002/hep.28675DOI Listing
September 2016