5-oxoETE triggers nociception in constipation-predominant irritable bowel syndrome through MAS-related G protein-coupled receptor D.

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that is characterized by chronic abdominal pain concurrent with altered bowel habit. Polyunsaturated fatty acid (PUFA) metabolites are increased in abundance in IBS and are implicated in the alteration of sensation to mechanical stimuli, which is defined as visceral hypersensitivity. We sought to quantify PUFA metabolites in patients with IBS and evaluate their role in pain. Quantification of PUFA metabolites by mass spectrometry in colonic biopsies showed an increased abundance of 5-oxoeicosatetraenoic acid (5-oxoETE) only in biopsies taken from patients with IBS with predominant constipation (IBS-C). Local administration of 5-oxoETE to mice induced somatic and visceral hypersensitivity to mechanical stimuli without causing tissue inflammation. We found that 5-oxoETE directly acted on both human and mouse sensory neurons as shown by lumbar splanchnic nerve recordings and Ca2+ imaging of dorsal root ganglion (DRG) neurons. We showed that 5-oxoETE selectively stimulated nonpeptidergic, isolectin B4 (IB4)-positive DRG neurons through a phospholipase C (PLC)- and pertussis toxin-dependent mechanism, suggesting that the effect was mediated by a G protein-coupled receptor (GPCR). The MAS-related GPCR D (Mrgprd) was found in mouse colonic DRG afferents and was identified as being implicated in the noxious effects of 5-oxoETE. Together, these data suggest that 5-oxoETE, a potential biomarker of IBS-C, induces somatic and visceral hyperalgesia without inflammation in an Mrgprd-dependent manner. Thus, 5-oxoETE may play a pivotal role in the abdominal pain associated with IBS-C.BBSRC BB/R006210/1 to James R F Hockley and Ewan St John Smith Rosetrees 834 Postdoctoral Grant (A1296) awarded to James R F Hockley and Ewan St John Smit

Les systèmes microparticulaires pour la libération colonique

Crohn's disease and ulcerative colitis are two related but distinct chronic inflammatory disorders of gastrointestinal tract (GIT), commonly denoted as inflammatory bowel disease(IBD). The main goal of the anti-inflammatory treatment of this disorder is to achieve maximal drug concentration in inflamed area and reduce systemic adverse effects. For this purpose several colon-spécifie drug delivery systems have been investigated. In addition, the design of pellets as oral drug delivery systems may provide many advantages over single unit preparations and thus improve patient compliance. It is well known that most existing treatments of IBD are associated with significant side effects and for this reason the formulation with a " food like " composition was designed. In the first part of our study, therapeutic efficiency of rutin/chitosan pellets with coatings based on natural polysaccharides degraded by colonie microbiota compared to commercialized 5-aminosalicylic acid (5-ASA) pellets was investigated. Release profiles ofcoated pellets showed a minimal drug release in simulated stomach and small intestine following by rapid drug release upon exposure to the colonie fluid. The results from in vivo testing showed that rutin attenuated efficiently inflammation in the colon and coated pellets were as effective as 5-ASA pellets in mitigating experimental colitis. The studies demonstrated that rutin administration via chitosan core coated pellets seems to be apromising approach for colon-specific delivery since they could interact easily with the mucin layer and deliver drug especially to the inflamed colonie area to relieve symptoms of IBD omitting side effects related to conventional treatment. The second objective of this thesis was to explore the impact of additional mucoadhesive polymer chitosan in the pellets core on the therapeutic efficiency. For this purpose, 5-ASA loaded pellets were produced by extrusion/spheronisation method and subsequently coated with pH-sensitive polymer Eudragit® FS. No drug release at pH 1.2within 2 h, and release as intended in the simulated distal ileum and colon was observed. Chitosan-core pellets showed efficient mucoadhesive properties in ex vivo bioadhesion testing which were also confirmed by increased concentration of 5-ASA metabolite in the colonie tissues in rats. The pellets were tested in preexisting colitis and the results revealed significant attenuation of the colonie inflammation. We can conclude, that bioadhesive chitosan-corepellets showed additional beneficial properties for colonie 5-ASA delivery in the treatment of IBD over marketed dosage formulation.La maladie de Crohn et la rectocolite hémorragique font partie des maladies inflammatoires chroniques de l'intestin (MICI). Le principal objectif des traitements anti-inflammatoires est de favoriser la délivrance du principe actif localement, spécifiquement sur les zones enflammées et de limiter les effets indésirables. Ainsi, plusieurs systèmes à libération colonique de molécules actives ont été développés. Parmi eux, les pellets présentent de nombreux avantages par rapport aux formes solides unitaires conventionnelles. Dans un premier temps, des pellets comptant une substance anti-inflammatoire naturelle et nutritive, la rutine, ont été développés. L'intérêt de cette molécule est de réduire considérablement les effets secondaires qui constituent un véritable problème dans les traitements actuels des MICI. Les pellets ont été enrobé avec les polysaccharides naturels se dégradant avec la flore colonique. Les études in vitro ont démontré une libération minimale du principe actif au niveau de l'estomac et du petit intestin. Par contre, une libération rapide et totale a été observée lors de l'exposition des pellets dans les conditions du milieu colonique. Les résultats des tests in vivo ont démontré que la rutine a atténué considérablement l'inflammation au niveau de colon et les pellets enrobés ont été aussi efficaces que les pellets d'acide 5-aminosalicylique (5-ASA) commercialisés. L'administration orale de rutine via les pellets enrobés et préparés avec le chitosan semble être une approche prometteuse, permettant la libération du principe actif au niveau des zones enflammées, pour le traitement des MICI tout en réduisant les effets secondaires. Le deuxième but de notre travail était d'élucider l'impact du chitosan, un polymère mucoadhésif, sur l'efficacité thérapeutique. Les pellets de 5-ASA ont été préparés à partir de cellulose microcristalline avec ou sans chitosan. Un enrobage constitué d'un polymère pH dépendant,1' Eudragit® FS, a ensuite été réalisé autour du noyau. Les tests de dissolution ont montré que le principe actif n'était pas libéré du pellet après 2 h en milieu acide. En revanche,la libération était rapide dans un milieu simulant l'environnement colonique. Les tests ex vivo avec les pellets contenant le chitosan ont montré des propriétés mucoadhésives importantes qui ont été confirmées par la concentration élevée du métabolite de 5-ASA dans les tissus coloniques des rats. De plus, nous avons a démontré que les pellets permettaient d'atténuer de façon significative l'inflammation du côlon. Ainsi, les pellets bioadhésifs enrobés possèdent des propriétés bénéfiques supplémentaires pour la libération du 5-ASA au niveau du côlon par rapport à des formes multidoses commercialisées pour le traitement des MICI

Multiparticulate colon drug delivery systems

La maladie de Crohn et la rectocolite hémorragique font partie des maladies inflammatoires chroniques de l'intestin (MICI). Le principal objectif des traitements anti-inflammatoires est de favoriser la délivrance du principe actif localement, spécifiquement sur les zones enflammées et de limiter les effets indésirables. Ainsi, plusieurs systèmes à libération colonique de molécules actives ont été développés. Parmi eux, les pellets présentent de nombreux avantages par rapport aux formes solides unitaires conventionnelles. Dans un premier temps, des pellets comptant une substance anti-inflammatoire naturelle et nutritive, la rutine, ont été développés. L'intérêt de cette molécule est de réduire considérablement les effets secondaires qui constituent un véritable problème dans les traitements actuels des MICI. Les pellets ont été enrobé avec les polysaccharides naturels se dégradant avec la flore colonique. Les études in vitro ont démontré une libération minimale du principe actif au niveau de l'estomac et du petit intestin. Par contre, une libération rapide et totale a été observée lors de l'exposition des pellets dans les conditions du milieu colonique. Les résultats des tests in vivo ont démontré que la rutine a atténué considérablement l'inflammation au niveau de colon et les pellets enrobés ont été aussi efficaces que les pellets d'acide 5-aminosalicylique (5-ASA) commercialisés. L'administration orale de rutine via les pellets enrobés et préparés avec le chitosan semble être une approche prometteuse, permettant la libération du principe actif au niveau des zones enflammées, pour le traitement des MICI tout en réduisant les effets secondaires. Le deuxième but de notre travail était d'élucider l'impact du chitosan, un polymère mucoadhésif, sur l'efficacité thérapeutique. Les pellets de 5-ASA ont été préparés à partir de cellulose microcristalline avec ou sans chitosan. Un enrobage constitué d'un polymère pH dépendant,1' Eudragit® FS, a ensuite été réalisé autour du noyau. Les tests de dissolution ont montré que le principe actif n'était pas libéré du pellet après 2 h en milieu acide. En revanche,la libération était rapide dans un milieu simulant l'environnement colonique. Les tests ex vivo avec les pellets contenant le chitosan ont montré des propriétés mucoadhésives importantes qui ont été confirmées par la concentration élevée du métabolite de 5-ASA dans les tissus coloniques des rats. De plus, nous avons a démontré que les pellets permettaient d'atténuer de façon significative l'inflammation du côlon. Ainsi, les pellets bioadhésifs enrobés possèdent des propriétés bénéfiques supplémentaires pour la libération du 5-ASA au niveau du côlon par rapport à des formes multidoses commercialisées pour le traitement des MICI.Crohn's disease and ulcerative colitis are two related but distinct chronic inflammatory disorders of gastrointestinal tract (GIT), commonly denoted as inflammatory bowel disease(IBD). The main goal of the anti-inflammatory treatment of this disorder is to achieve maximal drug concentration in inflamed area and reduce systemic adverse effects. For this purpose several colon-spécifie drug delivery systems have been investigated. In addition, the design of pellets as oral drug delivery systems may provide many advantages over single unit preparations and thus improve patient compliance. It is well known that most existing treatments of IBD are associated with significant side effects and for this reason the formulation with a " food like " composition was designed. In the first part of our study, therapeutic efficiency of rutin/chitosan pellets with coatings based on natural polysaccharides degraded by colonie microbiota compared to commercialized 5-aminosalicylic acid (5-ASA) pellets was investigated. Release profiles ofcoated pellets showed a minimal drug release in simulated stomach and small intestine following by rapid drug release upon exposure to the colonie fluid. The results from in vivo testing showed that rutin attenuated efficiently inflammation in the colon and coated pellets were as effective as 5-ASA pellets in mitigating experimental colitis. The studies demonstrated that rutin administration via chitosan core coated pellets seems to be apromising approach for colon-specific delivery since they could interact easily with the mucin layer and deliver drug especially to the inflamed colonie area to relieve symptoms of IBD omitting side effects related to conventional treatment. The second objective of this thesis was to explore the impact of additional mucoadhesive polymer chitosan in the pellets core on the therapeutic efficiency. For this purpose, 5-ASA loaded pellets were produced by extrusion/spheronisation method and subsequently coated with pH-sensitive polymer Eudragit® FS. No drug release at pH 1.2within 2 h, and release as intended in the simulated distal ileum and colon was observed. Chitosan-core pellets showed efficient mucoadhesive properties in ex vivo bioadhesion testing which were also confirmed by increased concentration of 5-ASA metabolite in the colonie tissues in rats. The pellets were tested in preexisting colitis and the results revealed significant attenuation of the colonie inflammation. We can conclude, that bioadhesive chitosan-corepellets showed additional beneficial properties for colonie 5-ASA delivery in the treatment of IBD over marketed dosage formulation

Multiparticulate systems containing 5-aminosalicylic acid for the treatment of inflammatory bowel disease

In recent years, many achievements have been realized in the therapy of inflammatory bowel disease (IBD) although its etiology remains unknown. Thus IBD treatment is symptomatic and targets general inflammatory mechanisms. Oral formulations containing 5-aminosalicylic acid (5-ASA) have become the standard therapy for mild-to-moderate IBD

Les systèmes microparticulaires pour la libération colonique

La maladie de Crohn et la rectocolite hémorragique font partie des maladies inflammatoires chroniques de l'intestin (MICI). Le principal objectif des traitements anti-inflammatoires est de favoriser la délivrance du principe actif localement, spécifiquement sur les zones enflammées et de limiter les effets indésirables. Ainsi, plusieurs systèmes à libération colonique de molécules actives ont été développés. Parmi eux, les pellets présentent de nombreux avantages par rapport aux formes solides unitaires conventionnelles. Dans un premier temps, des pellets comptant une substance anti-inflammatoire naturelle et nutritive, la rutine, ont été développés. L'intérêt de cette molécule est de réduire considérablement les effets secondaires qui constituent un véritable problème dans les traitements actuels des MICI. Les pellets ont été enrobé avec les polysaccharides naturels se dégradant avec la flore colonique. Les études in vitro ont démontré une libération minimale du principe actif au niveau de l'estomac et du petit intestin. Par contre, une libération rapide et totale a été observée lors de l'exposition des pellets dans les conditions du milieu colonique. Les résultats des tests in vivo ont démontré que la rutine a atténué considérablement l'inflammation au niveau de colon et les pellets enrobés ont été aussi efficaces que les pellets d'acide 5-aminosalicylique (5-ASA) commercialisés. L'administration orale de rutine via les pellets enrobés et préparés avec le chitosan semble être une approche prometteuse, permettant la libération du principe actif au niveau des zones enflammées, pour le traitement des MICI tout en réduisant les effets secondaires. Le deuxième but de notre travail était d'élucider l'impact du chitosan, un polymère mucoadhésif, sur l'efficacité thérapeutique. Les pellets de 5-ASA ont été préparés à partir de cellulose microcristalline avec ou sans chitosan. Un enrobage constitué d'un polymère pH dépendant,1' Eudragit® FS, a ensuite été réalisé autour du noyau. Les tests de dissolution ont montré que le principe actif n'était pas libéré du pellet après 2 h en milieu acide. En revanche,la libération était rapide dans un milieu simulant l'environnement colonique. Les tests ex vivo avec les pellets contenant le chitosan ont montré des propriétés mucoadhésives importantes qui ont été confirmées par la concentration élevée du métabolite de 5-ASA dans les tissus coloniques des rats. De plus, nous avons a démontré que les pellets permettaient d'atténuer de façon significative l'inflammation du côlon. Ainsi, les pellets bioadhésifs enrobés possèdent des propriétés bénéfiques supplémentaires pour la libération du 5-ASA au niveau du côlon par rapport à des formes multidoses commercialisées pour le traitement des MICI.Crohn's disease and ulcerative colitis are two related but distinct chronic inflammatory disorders of gastrointestinal tract (GIT), commonly denoted as inflammatory bowel disease(IBD). The main goal of the anti-inflammatory treatment of this disorder is to achieve maximal drug concentration in inflamed area and reduce systemic adverse effects. For this purpose several colon-spécifie drug delivery systems have been investigated. In addition, the design of pellets as oral drug delivery systems may provide many advantages over single unit preparations and thus improve patient compliance. It is well known that most existing treatments of IBD are associated with significant side effects and for this reason the formulation with a " food like " composition was designed. In the first part of our study, therapeutic efficiency of rutin/chitosan pellets with coatings based on natural polysaccharides degraded by colonie microbiota compared to commercialized 5-aminosalicylic acid (5-ASA) pellets was investigated. Release profiles ofcoated pellets showed a minimal drug release in simulated stomach and small intestine following by rapid drug release upon exposure to the colonie fluid. The results from in vivo testing showed that rutin attenuated efficiently inflammation in the colon and coated pellets were as effective as 5-ASA pellets in mitigating experimental colitis. The studies demonstrated that rutin administration via chitosan core coated pellets seems to be apromising approach for colon-specific delivery since they could interact easily with the mucin layer and deliver drug especially to the inflamed colonie area to relieve symptoms of IBD omitting side effects related to conventional treatment. The second objective of this thesis was to explore the impact of additional mucoadhesive polymer chitosan in the pellets core on the therapeutic efficiency. For this purpose, 5-ASA loaded pellets were produced by extrusion/spheronisation method and subsequently coated with pH-sensitive polymer Eudragit® FS. No drug release at pH 1.2within 2 h, and release as intended in the simulated distal ileum and colon was observed. Chitosan-core pellets showed efficient mucoadhesive properties in ex vivo bioadhesion testing which were also confirmed by increased concentration of 5-ASA metabolite in the colonie tissues in rats. The pellets were tested in preexisting colitis and the results revealed significant attenuation of the colonie inflammation. We can conclude, that bioadhesive chitosan-corepellets showed additional beneficial properties for colonie 5-ASA delivery in the treatment of IBD over marketed dosage formulation.BESANCON-Bib. Electronique (250560099) / SudocSudocFranceF

Bioadhesive pellets increase local 5-aminosalicylic acid concentration in experimental colitis

Topical delivery of 5-aminosalicylic acid (5-ASA) to the colonic mucosa is important in order to achieve effective drug concentration in the site of inflammation and to minimize its systemic availability. 5-ASA loaded pellets were prepared by an extrusion/spheronization method. Mucoadhesive biopolymer chitosan was incorporated into the pellets, and drug delivery to the colon was controlled by the pH-sensitive polymer Eudragit® FS. Dissolution profiles of coated pellets revealed no drug release at pH 1.2 within 2h and release as intended in the simulated distal ileum and colon. In vivo, chitosan-core drug loaded pellets (AMCh) showed 2.5-fold higher drug metabolite concentration than after chitosan free pellets (AM) administration in the inflamed colonic tissue. Additionally, AMCh demonstrated decreased in AUC in colitis group (1507 ± 400 ng h/ml) compared with AM (1907 ± 122 ng h/ml). In terms of therapeutic efficiency, administration of pellets markedly decreased the colon/body weight ratio (colitis: 0.0355 ± 0.0028; AM 0.0092 ± 0.0033; AMCh 0.0086 ± 0.0022) and myeloperoxidase activity (colitis: 3212 ± 294 U/g tissue; AM 796 ± 211 U/g; AMCh 552 ± 319 U/g). Bioadhesive chitosan pellets showed additional beneficial properties for colonic 5-ASA delivery in the treatment of inflammatory bowel disease by increasing the drug concentration locally

Coated chitosan pellets containing rutin intended for the treatment of inflammatory bowel disease: in vitro characteristics and in vivo evaluation

Preparation of coated pellets intended for rutin colon delivery, their evaluation in vitro and in vivo in experimental colitis in rats was the purpose of this study. Pellets were obtained using extrusion/spheronization and coated with three types of coatings (caffeic acid/hypromellose/alginic acid; sodium alginate/hypromellose/zinc acetate; sodium alginate/chitosan). Dissolution using buffers of pH values, β-glucosidase and times corresponding to gastrointestinal tract (GIT) was provided. Pellets coated with alginate/chitosan showed low rutin dissolution (12-14%) in upper GIT conditions and fast release (87-89%) under colon conditions; that is a good presumption of intended rutin release. After colitis induction and development, the rats were treated with pellets and rutin solution administered orally, solution also rectally. Colon/body weight ratio, myeloperoxidase activity and histological evaluation were performed. Rutin was able to promote colonic healing at the dose of 10mg/kg: colon/body weight ratio decreased and myeloperoxidase activity was significantly suppressed. Pellets coated with alginate/chitosan applied orally and rutin solution administered rectally showed the best efficacy. The combination of rutin as natural product, mucoadhesive chitosan degraded in the colon and sodium alginate as the main coating substance in the form of pellets create a promising preparation for therapy of this severe illness

Protease-activated receptor 1 is implicated in irritable bowel syndrome mediators-induced signaling to thoracic human sensory neurons

Proteases and protease-activated receptors (PARs) are major mediators involved in irritable bowel syndrome (IBS). Our objectives were to decipher the expression and functionality (calcium signaling) of PARs in human dorsal root ganglia (DRG) neurons and to define mechanisms involved in human sensory neuron signaling by IBS patient mediators. Human thoracic DRG were obtained from the national disease resource interchange. Expression of PAR1, PAR2, and PAR4 was assessed by immunohistochemistry and quantitative reverse transcription PCR (RT-qPCR) in whole DRG or in primary cultures of isolated neurons. Calcium signaling in response to PAR agonist peptides (PAR-AP), their inactive peptides (PAR-IP), thrombin (10 U/mL), supernatants from colonic biopsies of patients with IBS, or healthy controls, with or without PAR1 or PAR4 antagonist were studied in cultured human DRG neurons. PAR1, PAR2, and PAR4 were all expressed in human DRG, respectively, in 20%, 40%, and 40% of the sensory neurons. PAR1-AP increased intracellular calcium concentration in a dose-dependent manner. This increase was inhibited by PAR1 antagonism. By contrast, PAR2-AP, PAR4-AP, and PAR-IP did not cause calcium mobilization. PAR1-AP-induced calcium flux was significantly reduced by preincubation with PAR4-AP, but not with PAR2-AP. Thrombin increased calcium flux, which was inhibited by a PAR1 antagonist and increased by a PAR4 antagonist. Supernatants from colonic biopsies of patients with IBS induced calcium flux in human sensory neurons compared with healthy controls, and this induction was reversed by a PAR1 antagonist. Taken together, our results highlight that PAR1 antagonism should be investigated as a new therapeutic target for IBS symptoms

Galanin enhances systemic glucose metabolism through enteric Nitric Oxide Synthase-expressed neurons.

Objective: Decreasing duodenal contraction is now considered as a major focus for the treatment of type 2 diabetes. Therefore, identifying bioactive molecules able to target the enteric nervous system, which controls the motility of intestinal smooth muscle cells, represents a new therapeutic avenue. For this reason, we chose to study the impact of oral galanin on this system in diabetic mice. Methods: Enteric neurotransmission, duodenal contraction, glucose absorption, modification of gutebrain axis, and glucose metabolism (glucose tolerance, insulinemia, glucose entry in tissue, hepatic glucose metabolism) were assessed. Results: We show that galanin, a neuropeptide expressed in the small intestine, decreases duodenal contraction by stimulating nitric oxide release from enteric neurons. This is associated with modification of hypothalamic nitric oxide release that favors glucose uptake in metabolic tissues such as skeletal muscle, liver, and adipose tissue. Oral chronic gavage with galanin in diabetic mice increases insulin sensitivity, which is associated with an improvement of several metabolic parameters such as glucose tolerance, fasting blood glucose, and insulin. Conclusion: Here, we demonstrate that oral galanin administration improves glucose homeostasis via the enteric nervous system and could be considered a therapeutic potential for the treatment of T2D