Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.449
Filtrar
1.
Am J Physiol Gastrointest Liver Physiol ; 319(2): G227-G237, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32597706

RESUMO

Antibiotic treatment is a standard therapy for Clostridioides difficile infection, but dysbiosis of the gut microbiota due to antibiotic exposure is also a major risk factor for the disease. Following an initial episode of C. difficile infection, a relentless cycle of recurrence can occur, where persistent treatment-related dysbiosis predisposes the patient to subsequent relapse. This study uses a longitudinal study design to compare the effects of a narrow-spectrum (ridinilazole) or broad-spectrum antibiotic (vancomycin) on intestinal bile acid profiles and their associations with gut bacteria over the course of C. difficile infection treatment. At the end of treatment (day 10), subjects receiving vancomycin showed a nearly 100-fold increase in the ratio of conjugated to secondary bile acids in their stool compared with baseline, whereas subjects receiving ridinilazole maintained this ratio near baseline levels. Correlation analysis detected significant positive associations between secondary bile acids and several Bacteroidales and Clostridiales families. These families were depleted in the vancomycin group but preserved at near-baseline abundance in the ridinilazole group. Enterobacteriaceae, which expanded to a greater extent in the vancomycin group, correlated negatively and positively with secondary and conjugated primary bile acids, respectively. Bile acid ratios at the end of treatment were significantly different between those who recurred and those who did not. These results indicate that a narrow-spectrum antibiotic maintains an intestinal bile acid profile associated with a lowered risk of recurrence.NEW & NOTEWORTHY This is the first study to demonstrate in humans the relationships between Clostridioides difficile antibiotic treatment choice and bile acid metabolism both during therapy and after treatment cessation. The results show a microbiota- and metabolome-preserving property of a novel narrow-spectrum agent that correlates with the agent's favorable sustained clinical response rates compared with broad-spectrum antibiotic treatment.


Assuntos
Antibacterianos/farmacologia , Benzimidazóis/farmacologia , Ácidos e Sais Biliares/química , Clostridiales/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Piridinas/farmacologia , Ácidos e Sais Biliares/metabolismo , Fezes/química , Microbioma Gastrointestinal/fisiologia , Humanos
2.
Nature ; 582(7813): 566-570, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32555455

RESUMO

The gut microbiota synthesize hundreds of molecules, many of which influence host physiology. Among the most abundant metabolites are the secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA), which accumulate at concentrations of around 500 µM and are known to block the growth of Clostridium difficile1, promote hepatocellular carcinoma2 and modulate host metabolism via the G-protein-coupled receptor TGR5 (ref. 3). More broadly, DCA, LCA and their derivatives are major components of the recirculating pool of bile acids4; the size and composition of this pool are a target of therapies for primary biliary cholangitis and nonalcoholic steatohepatitis. Nonetheless, despite the clear impact of DCA and LCA on host physiology, an incomplete knowledge of their biosynthetic genes and a lack of genetic tools to enable modification of their native microbial producers limit our ability to modulate secondary bile acid levels in the host. Here we complete the pathway to DCA and LCA by assigning and characterizing enzymes for each of the steps in its reductive arm, revealing a strategy in which the A-B rings of the steroid core are transiently converted into an electron acceptor for two reductive steps carried out by Fe-S flavoenzymes. Using anaerobic in vitro reconstitution, we establish that a set of six enzymes is necessary and sufficient for the eight-step conversion of cholic acid to DCA. We then engineer the pathway into Clostridium sporogenes, conferring production of DCA and LCA on a nonproducing commensal and demonstrating that a microbiome-derived pathway can be expressed and controlled heterologously. These data establish a complete pathway to two central components of the bile acid pool.


Assuntos
Ácidos e Sais Biliares/química , Ácidos e Sais Biliares/metabolismo , Microbioma Gastrointestinal/genética , Microbioma Gastrointestinal/fisiologia , Hidroxilação/genética , Redes e Vias Metabólicas/genética , Animais , Clostridium/enzimologia , Clostridium/genética , Clostridium/metabolismo , Ácido Desoxicólico/química , Ácido Desoxicólico/metabolismo , Ácido Litocólico/química , Ácido Litocólico/metabolismo , Masculino , Engenharia Metabólica , Camundongos , Óperon/genética , Simbiose
3.
Nature ; 581(7809): 475-479, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32461639

RESUMO

Intestinal health relies on the immunosuppressive activity of CD4+ regulatory T (Treg) cells1. Expression of the transcription factor Foxp3 defines this lineage, and can be induced extrathymically by dietary or commensal-derived antigens in a process assisted by a Foxp3 enhancer known as conserved non-coding sequence 1 (CNS1)2-4. Products of microbial fermentation including butyrate facilitate the generation of peripherally induced Treg (pTreg) cells5-7, indicating that metabolites shape the composition of the colonic immune cell population. In addition to dietary components, bacteria modify host-derived molecules, generating a number of biologically active substances. This is epitomized by the bacterial transformation of bile acids, which creates a complex pool of steroids8 with a range of physiological functions9. Here we screened the major species of deconjugated bile acids for their ability to potentiate the differentiation of pTreg cells. We found that the secondary bile acid 3ß-hydroxydeoxycholic acid (isoDCA) increased Foxp3 induction by acting on dendritic cells (DCs) to diminish their immunostimulatory properties. Ablating one receptor, the farnesoid X receptor, in DCs enhanced the generation of Treg cells and imposed a transcriptional profile similar to that induced by isoDCA, suggesting an interaction between this bile acid and nuclear receptor. To investigate isoDCA in vivo, we took a synthetic biology approach and designed minimal microbial consortia containing engineered Bacteroides strains. IsoDCA-producing consortia increased the number of colonic RORγt-expressing Treg cells in a CNS1-dependent manner, suggesting enhanced extrathymic differentiation.


Assuntos
Bactérias/metabolismo , Ácidos e Sais Biliares/química , Ácidos e Sais Biliares/metabolismo , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologia , Sequência de Aminoácidos , Animais , Bacteroides/metabolismo , Colo/microbiologia , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Feminino , Fermentação , Microbioma Gastrointestinal , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Consórcios Microbianos , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo
4.
Artigo em Inglês | MEDLINE | ID: mdl-32220802

RESUMO

Metabolic profiling is commonly achieved by mass spectrometry (MS) following reversed-phase (RP) and hydrophilic interaction chromatography (HILIC) either performed independently, leading to overlapping datasets, or in a coupled configuration, requiring multiple liquid chromatography (LC) systems. To overcome these limitations, we developed a single, 20-minute chromatographic method using an in-line RP-ion-exchange (IEX) column arrangement and a single LC system. This configuration separates clinically significant polar and non-polar compounds without derivatization or ion-pairing reagents, allowing ionization in both polarities. An in-house library was created with 397 authentic standards, including acylcarnitines, amino acids, bile acids, nucleosides, organic acids, steroid hormones, and vitamins. Analysis of pooled plasma and urine samples revealed 5445 and 4111 ion features, leading to 88 and 82 confirmed metabolite identifications, respectively. Metabolites were detected at clinically relevant concentrations with good precision, and good chromatographic separation was demonstrated for clinically significant isomers including methylmalonic acid and succinic acid, as well as alloisoleucine and isoleucine/leucine. Evaluation of the samples by unsupervised principal component analysis showed excellent analytical quality.


Assuntos
Isoleucina/sangue , Isoleucina/urina , Metabolômica/métodos , Ácido Metilmalônico/sangue , Ácido Metilmalônico/urina , Ácido Succínico/sangue , Ácido Succínico/urina , Aminoácidos/química , Ácidos e Sais Biliares/química , Carnitina/análogos & derivados , Carnitina/química , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Cromatografia de Fase Reversa , Hormônios/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Metaboloma , Nucleosídeos/química , Bibliotecas de Moléculas Pequenas/química , Espectrometria de Massas em Tandem , Vitaminas/química
5.
Nature ; 579(7797): 123-129, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32103176

RESUMO

A mosaic of cross-phylum chemical interactions occurs between all metazoans and their microbiomes. A number of molecular families that are known to be produced by the microbiome have a marked effect on the balance between health and disease1-9. Considering the diversity of the human microbiome (which numbers over 40,000 operational taxonomic units10), the effect of the microbiome on the chemistry of an entire animal remains underexplored. Here we use mass spectrometry informatics and data visualization approaches11-13 to provide an assessment of the effects of the microbiome on the chemistry of an entire mammal by comparing metabolomics data from germ-free and specific-pathogen-free mice. We found that the microbiota affects the chemistry of all organs. This included the amino acid conjugations of host bile acids that were used to produce phenylalanocholic acid, tyrosocholic acid and leucocholic acid, which have not previously been characterized despite extensive research on bile-acid chemistry14. These bile-acid conjugates were also found in humans, and were enriched in patients with inflammatory bowel disease or cystic fibrosis. These compounds agonized the farnesoid X receptor in vitro, and mice gavaged with the compounds showed reduced expression of bile-acid synthesis genes in vivo. Further studies are required to confirm whether these compounds have a physiological role in the host, and whether they contribute to gut diseases that are associated with microbiome dysbiosis.


Assuntos
Ácidos e Sais Biliares/biossíntese , Ácidos e Sais Biliares/química , Metabolômica , Microbiota/fisiologia , Animais , Ácidos e Sais Biliares/metabolismo , Ácido Cólico/biossíntese , Ácido Cólico/química , Ácido Cólico/metabolismo , Fibrose Cística/genética , Fibrose Cística/metabolismo , Fibrose Cística/microbiologia , Vida Livre de Germes , Humanos , Doenças Inflamatórias Intestinais/genética , Doenças Inflamatórias Intestinais/metabolismo , Doenças Inflamatórias Intestinais/microbiologia , Camundongos , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo
6.
Nat Commun ; 11(1): 1104, 2020 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-32107377

RESUMO

Structural elucidation and molecular scrutiny of cerebral vasculature is crucial for understanding the functions and diseases of the brain. Here, we introduce SeeNet, a method for near-complete three-dimensional visualization of cerebral vascular networks with high signal-to-noise ratios compatible with molecular phenotyping. SeeNet employs perfusion of a multifunctional crosslinker, vascular casting by temperature-controlled polymerization of hybrid hydrogels, and a bile salt-based tissue-clearing technique optimized for observation of vascular connectivity. SeeNet is capable of whole-brain visualization of molecularly characterized cerebral vasculatures at the single-microvessel level. Moreover, SeeNet reveals a hitherto unidentified vascular pathway bridging cerebral and hippocampal vessels, thus serving as a potential tool to evaluate the connectivity of cerebral vasculature.


Assuntos
Encéfalo/diagnóstico por imagem , Capilares/diagnóstico por imagem , Circulação Cerebrovascular , Técnicas de Preparação Histocitológica/métodos , Imageamento Tridimensional , Animais , Ácidos e Sais Biliares/química , Encéfalo/irrigação sanguínea , Encéfalo/patologia , Reagentes para Ligações Cruzadas/química , Corantes Fluorescentes/química , Hidrogéis/química , Substâncias Luminescentes/química , Proteínas Luminescentes/química , Proteínas Luminescentes/genética , Camundongos , Microscopia de Fluorescência/métodos , Perfusão , Polimerização , Razão Sinal-Ruído
7.
J Fish Biol ; 96(4): 1024-1033, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32072638

RESUMO

The American eel (Anguilla rostrata) is an imperilled fish hypothesized to use conspecific cues, in part, to coordinate long-distance migration during their multistage life history. Here, holding water and tissue from multiple American eel life stages was collected and analysed for the presence, profile and concentration of bile acids. Distinct bile acid profiles were identified in glass, elver, yellow eel and silver eel holding waters using ultraperformance liquid chromatography high-resolution mass spectrometry and principal component analysis. Taurochenodeoxycholic acid, taurodeoxycholic acid, cholic acid, deoxycholic acid, taurolithocholic acid and taurocholic acid were detected in whole tissue of American glass eels and elvers, and in liver, intestine and gallbladder samples of late-stage yellow eels. Bile acids were not a major component of silver eel washings or tissue. This study is novel because little was previously known about bile acids produced and emitted into the environment by American eels. Future behavioural studies could evaluate whether any bile acids produced by American eels influence conspecific migratory behaviour.


Assuntos
Anguilla/metabolismo , Ácidos e Sais Biliares/química , Ácidos e Sais Biliares/metabolismo , Animais , Fatores de Tempo
8.
Pharm Res ; 37(3): 42, 2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-31989335

RESUMO

PURPOSE: The design of biorelevant conditions for in vitro evaluation of orally administered drug products is contingent on obtaining accurate values for physiologically relevant parameters such as pH, buffer capacity and bile salt concentrations in upper gastrointestinal fluids. METHODS: The impact of sample handling on the measurement of pH and buffer capacity of aspirates from the upper gastrointestinal tract was evaluated, with a focus on centrifugation and freeze-thaw cycling as factors that can influence results. Since bicarbonate is a key buffer system in the fasted state and is used to represent conditions in the upper intestine in vitro, variations on sample handling were also investigated for bicarbonate-based buffers prepared in the laboratory. RESULTS: Centrifugation and freezing significantly increase pH and decrease buffer capacity in samples obtained by aspiration from the upper gastrointestinal tract in the fasted state and in bicarbonate buffers prepared in vitro. Comparison of data suggested that the buffer system in the small intestine does not derive exclusively from bicarbonates. CONCLUSIONS: Measurement of both pH and buffer capacity immediately after aspiration are strongly recommended as "best practice" and should be adopted as the standard procedure for measuring pH and buffer capacity in aspirates from the gastrointestinal tract. Only data obtained in this way provide a valid basis for setting the physiological parameters in physiologically based pharmacokinetic models.


Assuntos
Bicarbonatos/química , Ácidos e Sais Biliares/química , Líquidos Corporais/química , Líquidos Corporais/metabolismo , Trato Gastrointestinal Superior/química , Trato Gastrointestinal Superior/metabolismo , Tampões (Química) , Famotidina/administração & dosagem , Famotidina/metabolismo , Absorção Gastrointestinal , Humanos , Concentração de Íons de Hidrogênio , Ibuprofeno/administração & dosagem , Ibuprofeno/metabolismo , Intestino Delgado , Sais/química , Estômago
9.
Lipids Health Dis ; 19(1): 9, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31941510

RESUMO

BACKGROUND: Previously, we found a significant relationship in a rat study between energy intake and bile acid (BA) metabolism especially 12α-hydroxylated (12αOH) BAs. The present study was designed to reveal relationships among BA metabolism, glucose tolerance, and cecal organic acids in rats fed a high-fat and high-sucrose diet (HFS) by using multivariate and multiple regression analyses in two types of glucose tolerance tests (GTTs). METHODS: Male WKAH/HkmSlc rats were fed with a control or a HFS for 13 weeks. Oral glucose tolerance test (OGTT) and intraperitoneal glucose tolerance test (IPGTT) were performed at week 9 and 11, respectively. BAs were analyzed by using ultra high-performance liquid chromatography-mass spectrometry. Organic acid concentrations in cecal contents were analyzed by using ultra high-performance liquid chromatography with post-column pH buffered electric conductivity method. RESULTS: A positive correlation of aortic 12αOH BA concentration was observed with energy intake and visceral adipose tissue weight. We found that an increase of 12αOH BAs in enterohepatic circulation, intestinal contents and feces in the HFS-fed rats compared to those in control rats regardless of no significant increase of total BA concentration in the feces in the test period. Fecal 12αOH BA concentration was positively correlated with maximal insulin level in OGTT and area under curve of insulin in IPGTT. There was a positive correlation between aortic 12αOH BAs concentration and changes in plasma glucose level in both OGTT and IPGTT. In contrast, a decrease in the concentration of organic acids was observed in the cecal contents of the HFS-fed rats. Multiple linear regression analysis in the IPGTT revealed that the concentrations of aortic 12αOH BA and cecal acetic acid were the predictors of insulin secretion. Moreover, there was a positive correlation between concentration of portal 12αOH BAs and change in insulin concentration of peripheral blood in the IPGTT. CONCLUSION: The distribution analysis of BA compositions accompanied by GTTs revealed a close relationship between 12αOH BA metabolism and insulin secretion in GTTs in rats.


Assuntos
Ácidos e Sais Biliares/metabolismo , Ingestão de Energia/genética , Metabolismo Energético/genética , Fígado/metabolismo , Animais , Ácidos e Sais Biliares/química , Glicemia/genética , Dieta Hiperlipídica/efeitos adversos , Sacarose na Dieta/farmacologia , Fezes/química , Teste de Tolerância a Glucose , Humanos , Resistência à Insulina/genética , Secreção de Insulina/genética , Gordura Intra-Abdominal/metabolismo , Gordura Intra-Abdominal/patologia , Fígado/patologia , Masculino , Ratos
10.
Colloids Surf B Biointerfaces ; 185: 110556, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31704607

RESUMO

Biomolecule derivatives are transversally used in nanotechnology. Deciphering their aggregation behavior is a crucial issue for the rational design of functional materials. To this end, it is necessary to build libraries of selectively functionalized analogues and infer general rules. In this work we enrich the highly applicative oriented collection of steroid derivatives, by reporting a rare example of C-12 selectively modified bile salt. While nature often exploits such position to encode functions, it is unusual and not trivial to prepare similar analogues in the laboratory. The introduction of a tert-butyl phenyl residue at C-12 provided a molecule with a self-assembly that remarkably switched from rigid pole-like structures to twisted ribbons at a biologically relevant critical temperature (∼25 °C). The system was characterized by microscopy and spectroscopy techniques and compared with the C-3 functionalized analogue. The twisted ribbons generate samples with a gel texture and a viscoelastic response. The parallel analysis of the two systems suggested that the observed thermoresponsive self-assemblies occur at similar critical temperatures and are probably dictated by the nature of the substituent, but involve aggregates with different structures depending on position and orientation of the substituent. This study highlights the self-assembly properties of two appealing thermoresponsive systems. Moreover, it adds fundamental insights hereto missing in the investigations of the relation between self-assembly and structure of synthetic steroids, which are valuable for the rational design of steroidal amphiphiles.


Assuntos
Ácidos e Sais Biliares/química , Esteroides/química , Tensoativos/química , Ácidos e Sais Biliares/síntese química , Difusão Dinâmica da Luz , Módulo de Elasticidade , Isomerismo , Esteroides/síntese química , Viscosidade
11.
Nature ; 577(7790): 410-415, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31875848

RESUMO

The metabolic pathways encoded by the human gut microbiome constantly interact with host gene products through numerous bioactive molecules1. Primary bile acids (BAs) are synthesized within hepatocytes and released into the duodenum to facilitate absorption of lipids or fat-soluble vitamins2. Some BAs (approximately 5%) escape into the colon, where gut commensal bacteria convert them into various intestinal BAs2 that are important hormones that regulate host cholesterol metabolism and energy balance via several nuclear receptors and/or G-protein-coupled receptors3,4. These receptors have pivotal roles in shaping host innate immune responses1,5. However, the effect of this host-microorganism biliary network on the adaptive immune system remains poorly characterized. Here we report that both dietary and microbial factors influence the composition of the gut BA pool and modulate an important population of colonic FOXP3+ regulatory T (Treg) cells expressing the transcription factor RORγ. Genetic abolition of BA metabolic pathways in individual gut symbionts significantly decreases this Treg cell population. Restoration of the intestinal BA pool increases colonic RORγ+ Treg cell counts and ameliorates host susceptibility to inflammatory colitis via BA nuclear receptors. Thus, a pan-genomic biliary network interaction between hosts and their bacterial symbionts can control host immunological homeostasis via the resulting metabolites.


Assuntos
Ácidos e Sais Biliares/metabolismo , Microbioma Gastrointestinal , Homeostase , Intestinos/imunologia , Intestinos/microbiologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/imunologia , Linfócitos T Reguladores/imunologia , Animais , Ácidos e Sais Biliares/química , Camundongos Endogâmicos C57BL , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética
12.
Molecules ; 24(24)2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31835427

RESUMO

Au nanoparticles (NPs) were prepared by UV light irradiation of a mixed solution of HAuCl4 and sodium deoxycholate (NaDC) under alkaline condition, in which NaDC served as both reducing agent and capping agent. The reaction was monitored by circular dichroism (CD) spectra, and it was found that the formed gold NPs could catalyze the oxidation of NaDC. A CD signal at ~283 nm in the UV region was observed for the oxidation product of NaDC. The intensity of the CD signal of the oxidation product was enhanced gradually with the reaction time. Electrospray ionization (ESI) mass spectra and nuclear magnetic resonance (NMR) spectra were carried out to determine the chemical composition of the oxidation product, revealing that NaDC was selectively oxidized to sodium 3-keto-12-hydroxy-cholanate (3-KHC). The chiral discrimination abilities of the micelles of NaDC and its oxidation product, 3-KHC, were investigated by using chiral model molecules R,S-1,1'-Binaphthyl-2,2'-diyl hydrogenphosphate (R,S-BNDHP). Compared with NaDC, the micelles of 3-KHC displayed higher binding ability to the chiral model molecules. In addition, the difference in binding affinity of 3-KHC micelles towards R,S-isomer was observed, and S-isomer was shown to preferentially bind to the micelles.


Assuntos
Ácidos e Sais Biliares/química , Ácido Desoxicólico/química , Ouro/química , Nanopartículas Metálicas/química , Micelas , Catálise , Nanopartículas Metálicas/ultraestrutura , Estrutura Molecular , Oxirredução , Análise Espectral
13.
Compr Physiol ; 10(1): 21-56, 2019 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-31853951

RESUMO

The intestinal reclamation of bile acids is crucial for the maintenance of their enterohepatic circulation. The majority of bile acids are actively absorbed via specific transport proteins that are highly expressed in the distal ileum. The uptake of bile acids by intestinal epithelial cells modulates the activation of cytosolic and membrane receptors such as the farnesoid X receptor (FXR) and G protein-coupled bile acid receptor 1 (GPBAR1), which has a profound effect on hepatic synthesis of bile acids as well as glucose and lipid metabolism. Extensive research has focused on delineating the processes of bile acid absorption and determining the contribution of dysregulated ileal signaling in the development of intestinal and hepatic disorders. For example, a decrease in the levels of the bile acid-induced ileal hormone FGF15/19 is implicated in bile acid-induced diarrhea (BAD). Conversely, the increase in bile acid absorption with subsequent overload of bile acids could be involved in the pathophysiology of liver and metabolic disorders such as fatty liver diseases and type 2 diabetes mellitus. This review article will attempt to provide a comprehensive overview of the mechanisms involved in the intestinal handling of bile acids, the pathological implications of disrupted intestinal bile acid homeostasis, and the potential therapeutic targets for the treatment of bile acid-related disorders. Published 2020. Compr Physiol 10:21-56, 2020.


Assuntos
Ácidos e Sais Biliares/metabolismo , Animais , Ácidos e Sais Biliares/química , Humanos , Absorção Intestinal , Fígado/metabolismo
14.
J Vet Intern Med ; 33(6): 2605-2617, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31674054

RESUMO

BACKGROUND: Tylosin is commonly prescribed to dogs with diarrhea. Orally administered antibiotics may alter the intestinal microbiota, which is responsible for crucial key bile acid (BA) biotransformation reactions. OBJECTIVES: To prospectively evaluate the impact of tylosin administration on fecal microbiota and unconjugated bile acids (UBAs) over time. ANIMALS: Sixteen healthy adult dogs. METHODS: Prospective, randomized controlled clinical trial. Dogs were randomized to receive 20 mg/kg of tylosin or a placebo capsule PO q12h for 7 days while undergoing daily fecal scoring. Fecal samples were collected on days 0, 7, 21, and 63. The microbiota was assessed using quantitative PCR and 16S rRNA gene sequencing. Unconjugated BAs were assessed using gas chromatography-mass spectrometry (GC-MS). RESULTS: Fecal scores were unchanged during placebo and tylosin administration. In the placebo group, no significant changes were observed in fecal microbiota or UBA concentrations. Day 7 samples from tylosin-exposed dogs exhibited decreased bacterial diversity (observed species, Chao1, Shannon, P < .001) characterized by decreases in anaerobes Fusobacteriaceae (linear discriminant analysis [LDA] score, 5.03) and Veillonellaceae (LDA score, 4.85). Primary UBA concentrations were increased at day 21 (median, [range]; 7.42, [0.67-18.77] µg/kg; P = .04) and day 63 (3.49 [0-28.43] µg/kg; P = .02) compared to day 0 (.14 [.03-1.19] µg/kg) in dogs receiving tylosin. At day 63, bacterial taxa were not significantly different compared to day 0, but the extent of microbial recovery was individualized. CONCLUSIONS AND CLINICAL IMPORTANCE: Tylosin causes fecal dysbiosis in healthy dogs with corresponding shifts in fecal UBAs. Changes did not uniformly resolve after discontinuation of tylosin.


Assuntos
Ácidos e Sais Biliares/química , Cães/microbiologia , Fezes/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Tilosina/farmacologia , Administração Oral , Animais , Antibacterianos/farmacologia , Feminino , Masculino
15.
Adv Colloid Interface Sci ; 274: 102045, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31689682

RESUMO

Because of their unusual chemical structure, bile salts (BS) play a fundamental role in intestinal lipid digestion and transport. BS have a planar arrangement of hydrophobic and hydrophilic moieties, which enables the BS molecules to form peculiar self-assembled structures in aqueous solutions. This molecular arrangement also has an influence on specific interactions of BS with lipid molecules and other compounds of ingested food and digestive media. Those comprise the complex scenario in which lipolysis occurs. In this review, we discuss the BS synthesis, composition, bulk interactions and mode of action during lipid digestion and transport. We look specifically into surfactant-related functions of BS that affect lipolysis, such as interactions with dietary fibre and emulsifiers, the interfacial activity in facilitating lipase and colipase anchoring to the lipid substrate interface, and finally the role of BS in the intestinal transport of lipids. Unravelling the roles of BS in the processing of lipids in the gastrointestinal tract requires a detailed analysis of their interactions with different compounds. We provide an update on the most recent findings concerning two areas of BS involvement: lipolysis and intestinal transport. We first explore the interactions of BS with various dietary fibres and food emulsifiers in bulk and at interfaces, as these appear to be key aspects for understanding interactions with digestive media. Next, we explore the interactions of BS with components of the intestinal digestion environment, and the role of BS in displacing material from the oil-water interface and facilitating adsorption of lipase. We look into the process of desorption, solubilisation of lipolysis, products and formation of mixed micelles. Finally, the BS-driven interactions of colloidal particles with the small intestinal mucus layer are considered, providing new findings for the overall assessment of the role of BS in lipid digestion and intestinal transport. This review offers a unique compilation of well-established and most recent studies dealing with the interactions of BS with food emulsifiers, nanoparticles and dietary fibre, as well as with the luminal compounds of the gut, such as lipase-colipase, triglycerides and intestinal mucus. The combined analysis of these complex interactions may provide crucial information on the pattern and extent of lipid digestion. Such knowledge is important for controlling the uptake of dietary lipids or lipophilic pharmaceuticals in the gastrointestinal tract through the engineering of novel food structures or colloidal drug-delivery systems.


Assuntos
Ácidos e Sais Biliares/metabolismo , Lipídeos/química , Lipólise , Animais , Ácidos e Sais Biliares/química , Transporte Biológico , Emulsificantes/química , Emulsificantes/metabolismo , Humanos
16.
Int J Nanomedicine ; 14: 6691-6706, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31692515

RESUMO

Purpose: Amentoflavone, robustaflavone, 2'',3''-dihydro-3',3'''-biapigenin, 3',3'''-binaringenin and delicaflavone are five major active ingredients in the total biflavonoids extract from Selaginella doederleinii (TBESD) with favorable anticancer properties. However, the natural-derived potent antitumor agent of TBESD is undesirable due to its poor solubility. The present study was to develop and optimize a proliposomal formulation of TBESD (P-TBESD) to improve its solubility, oral bioavailability and efficacy. Materials and methods: P-TBESD containing a bile salt, a protective hydrophilic isomalto-oligosaccharides (IMOs) coating, were successfully prepared by thin film dispersion-sonication method. The physicochemical and pharmacokinetic properties of P-TBESD were characterized, and the antitumor effect was evaluated using the HT-29 xenograft-bearing mice models in rats. Results: Compared with TBESD, the relative bioavailability of amentoflavone, robustaflavone, 2'',3''-dihydro-3',3'''-biapigenin, 3',3'''-binaringenin and delicaflavone from P-TBESD were 669%, 523%, 761%, 955% and 191%, respectively. The results of pharmacodynamics demonstrated that both TBESD and P-TBESD groups afforded antitumor effect without systemic toxicity, and the antitumor effect of P-TBESD was significantly superior to that of raw TBESD, based on the tumor growth inhibition and histopathological examination. Conclusion: Hence, IMOs-modified proliposomes have promising potential for TBESD solving the problem of its poor solubility and oral bioavailability, which can serve as a practical oral preparation for TBESD in the future cancer therapy.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Biflavonoides/administração & dosagem , Lipossomos/administração & dosagem , Extratos Vegetais/administração & dosagem , Selaginellaceae/química , Administração Oral , Animais , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacocinética , Biflavonoides/farmacocinética , Biflavonoides/farmacologia , Ácidos e Sais Biliares/química , Disponibilidade Biológica , Células HT29 , Humanos , Lipossomos/química , Lipossomos/farmacocinética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Oligossacarídeos/química , Extratos Vegetais/química , Ratos Sprague-Dawley , Solubilidade , Ensaios Antitumorais Modelo de Xenoenxerto
17.
Food Funct ; 10(11): 7299-7307, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31626262

RESUMO

BACKGROUND: Lactoferrin (LF) is a multifunctional glycoprotein that can regulate lipid metabolism, lower cholesterol, reduce body weight, and prevent atherosclerosis. Bile acid (BA) metabolism plays an important role in removing excess cholesterol from the body. However, studies on the effects of LF on BA metabolism are limited and inconsistent. METHODS: Male C57BL/6J mice aged 6-8 weeks were fed with a normal diet (control group), high-fat/high-cholesterol diet containing cholate (HFCCD group), or HFCCD and 1.0% LF in drinking water (LF group) for 8 weeks. Serum and hepatic lipid profiles, and glucose tolerance were measured. Fecal BA composition was determined through ultra-high performance liquid chromatography-tandem mass spectrometry. The gene expression of BA synthase in the liver and farnesoid X receptor (FXR)-mediated BA negative feedback regulation pathway in the liver and ileum were analyzed via RNA analysis. RESULTS: HFCCD resulted in abnormal cholesterol levels in the serum and liver. LF intervention significantly increased the serum high-density lipoprotein cholesterol level by 24.9% and decreased the hepatic total cholesterol content by 26%. LF treatment significantly increased the BA content per gram by 109.8%, the total amount of BA excretion by 153.5% and conjugated BAs by 87.6% in the feces. Furthermore, LF upregulated the expression of the hepatic sterol 12α-hydroxylase (CYP8B1) gene, which expresses important enzymes in the classical pathway of BA synthesis, and the bile acid-CoA amino acid N-acetyltransferase (BAAT) gene, which is responsible for the formation of conjugated BAs. The FXR-mediated pathways in the enterohepatic axis, including FXR, fibroblast growth factor 15, and fibroblast growth factor receptor 4, were inhibited by LF. CONCLUSIONS: LF ameliorated hepatic cholesterol deposition in mice fed with a high-fat and high cholesterol diet containing cholate. LF elevated the conjugated BA level, inhibited the ileum FXR and FXR-mediated enterohepatic axis, and increased BA synthesis and excretion.


Assuntos
Ácidos e Sais Biliares/metabolismo , Colesterol/metabolismo , Lactoferrina/farmacologia , Fígado/efeitos dos fármacos , Receptores Citoplasmáticos e Nucleares/metabolismo , Animais , Ácidos e Sais Biliares/química , Fezes/química , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Glucose/metabolismo , Metabolismo dos Lipídeos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL
18.
Food Funct ; 10(11): 7262-7274, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31620755

RESUMO

Most current research on food-relevant Pickering emulsions has been conducted using inorganic or food-compatible organic particles as emulsifiers. A key challenge is maintaining a favourable structure while being able to resist displacement or destabilisation by surfactants and controlling transport of substrates during digestion. Liposome stabilised emulsions have demonstrated some potential for being smart, responsive delivery systems for poorly available bioactives and drugs. We developed a liposome-stabilized oil-in-water Pickering emulsion utilising macromolecular crowding- with polyethylene glycol (PEG). They were pH-controllable and had surfactant-dependent deformability whilst displaying dual delivery routes from both the liposome and oil phases. Dynamic light scattering, confocal microscopy and emulsion stability measurements indicated the liposomes containing 10% PEG at neutral pH remained intact at the interface for extended time. Various degrees of interfacial coverage still existed in the presence of PEG, under acidic environment and with added bile salts. Emulsions with added PEG maintained a more integrated structure after in vitro oral-gastric digestion, and showed greater lipolysis with more free fatty acids (14.7 ± 0.5% for with PEG vs. 12.7 ± 0.1% for without PEG) released during in vitro intestinal digestion. These Pickering emulsions could provide a flexible approach to controlled release under a broad range of conditions.


Assuntos
Reatores Biológicos , Lipossomos/química , 1,2-Dipalmitoilfosfatidilcolina/análogos & derivados , 1,2-Dipalmitoilfosfatidilcolina/química , Ácidos e Sais Biliares/química , Emulsões/química , Concentração de Íons de Hidrogênio , Tamanho da Partícula , Polietilenoglicóis/química
19.
Int J Nanomedicine ; 14: 6555-6574, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31616143

RESUMO

Introduction: The intention of this work was to load olmesartan medoxomil (OLM), a sparsely water soluble antihypertensive bioactive with low oral bioavailability (26%), into PEGylated bilosomes (PBs) for augmenting its transdermal delivery. PBs contain PEGylated single chain edge activator besides the components of traditional bilosomes (Span 60, cholesterol and bile salts). The PEG gives further resilience to vesicle membrane and is speculated to augment both permeability and bioavailability of OLM. Methods: A 24 factorial experiment was constructed to inspect the impact of diverse variables on vesicles' features and sort out the optimal formula adopting Design Expert® software utilizing thin film hydration technique. Vesicles' evaluation was done by finding out entrapment efficiency percent (EE%), particle size (PS), polydispersity index (PDI), zeta potential (ZP) and amount of drug released after 6 hrs (Q6h). The optimal formula was selected and characterized for further investigations. Results: The optimal formula (PB15) showed spherical vesicles with EE% of 72.49±0.38%, PS of 559.30±10.70 nm, PDI of 0.57±0.15, ZP of -38.35±0.65 mV and Q6h of 59.60±0.24%. PB15 showed higher deformability index (28.39±5.71 g) compared to traditional bilosomes (5.88±0.90 g) and transethosomes (14.94±0.63 g). Further, PB15 showed superior skin permeation from rat's skin relative to the drug suspension. Moreover, confocal laser scanning microscopy examination revealed efficient penetration of the fluoro-labeled PB15 through skin. Histopathological study ensured the safety of PB15. In addition, in-vivo skin deposition studies showed higher OLM deposition in rat's skin from PB15 compared to transethosomes and OLM suspension. Furthermore, pharmacodynamic and pharmacokinetic studies performed using male Wistar rats and male Albino rabbits, respectively, showed the superiority of PB15 over oral tablets. PB15 was found to have significantly higher AUC0-48 and AUC0-∞ relative to the oral tablets. As well, the relative bioavailability of PB15 was found to be 235.04%. Conclusion: Overall, the obtained results confirmed the creditable effect of PB15 for transdermal delivery.


Assuntos
Ácidos e Sais Biliares/química , Sistemas de Liberação de Medicamentos , Olmesartana Medoxomila/administração & dosagem , Polietilenoglicóis/química , Administração Cutânea , Administração Oral , Animais , Anti-Hipertensivos/administração & dosagem , Disponibilidade Biológica , Varredura Diferencial de Calorimetria , Masculino , Olmesartana Medoxomila/farmacocinética , Olmesartana Medoxomila/farmacologia , Tamanho da Partícula , Permeabilidade , Coelhos , Ratos Wistar , Pele/efeitos dos fármacos , Absorção Cutânea , Comprimidos
20.
Eur J Pharm Biopharm ; 144: 91-100, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31521715

RESUMO

We have previously demonstrated that the ester conjugation of zidovudine (AZT) with ursodeoxycholic acid (UDCA) allows to obtain a prodrug (U-AZT) which eludes the active efflux transporters (AET). This allows the prodrug to more efficiently permeates and remains in murine macrophages than the parent compound. Here we demonstrate that U-AZT can be formulated, by a nanoprecipitation method, as nanoparticle cores coated by bile acid salt (taurocholate or ursodeoxycholate) corona, without any other excipients. The U-AZT nanoparticles appeared spherical with a mean diameter of ∼200 nm and a zeta potential of ∼-55 mV. During the incubation (5 h) in fetal bovine serum, the ursodeoxycholate-coated nanoparticle size did not change. Differently, taurocholate-coated particle size was firstly reduced and then increased up to 800 µm, thus suggesting the high aptitude of these nanoparticles to interact with serum proteins. The in vitro uptake of taurocholate coated particles by murine macrophages was strongly higher than that of ursodeoxycholate-coated particles or free U-AZT (∼500% and ∼7000%, respectively). AZT was also detected in macrophages following the prodrug uptake, with the greatest amounts observed after the taurocholate-coated nanoparticle incubation. As macrophages in the subarachnoid spaces of cerebrospinal fluid (CSF) constitute one of the most unreachable HIV sanctuaries in the body, we also tested the ability of taurocholate-coated nanoparticles (i.e., nanoparticles highly internalized by macrophages) to reach them after their nasal administration in the presence or absence of chitosan. The results indicate that chitosan allowed to obtain a relatively high uptake (up to 4 µg/ml) of U-AZT in CSF. Taking into account that chitosan may promote the direct brain nanoparticle uptake, these findings can be considered an initial step toward the in vivo targeting of the subarachnoid macrophages by U-AZT prodrug.


Assuntos
Ácidos e Sais Biliares/química , Encéfalo/metabolismo , Macrófagos/efeitos dos fármacos , Nanopartículas/química , Mucosa Nasal/metabolismo , Pró-Fármacos/farmacologia , Zidovudina/farmacologia , Administração Intranasal , Animais , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Linhagem Celular , Quitosana/química , Portadores de Fármacos/química , Excipientes/química , Camundongos , Nariz , Tamanho da Partícula , Ácido Ursodesoxicólico/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA