Pierre Desreumaux
Research interests
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InterestsCrohn Disease, IBD
Publications
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4.80Impact points
Targeting Peroxisome Proliferator-Activated Receptors (PPARs): Development of Modulators.
Journal of medicinal chemistry. 02/2012;
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4.64Impact points
AIEC colonization and pathogenicity: Influence of previous antibiotic treatment and preexisting inflammation.
Inflammatory bowel diseases. 02/2012;
BACKGROUND: Inflammatory bowel diseases (IBD) patients are abnormally colonized by adherent-invasive Escherichia coli (AIEC). NOD2 gene mutations impair intracellular bacterial clearance. We evaluated the impact of antibiotic treatment on AIEC colonization in wildtype (WT) and NOD2 knockout mice (NO... [more] BACKGROUND: Inflammatory bowel diseases (IBD) patients are abnormally colonized by adherent-invasive Escherichia coli (AIEC). NOD2 gene mutations impair intracellular bacterial clearance. We evaluated the impact of antibiotic treatment on AIEC colonization in wildtype (WT) and NOD2 knockout mice (NOD2KO) and the consequences on intestinal inflammation. METHODS: After 3 days of antibiotic treatment, mice were infected for 2 days with 109 CFU AIEC and sacrificed 1, 5, and 60 days later. In parallel, mice were challenged with AIEC subsequent to a dextran sodium sulfate (DSS) treatment and sacrificed 9 days later. Ileum, colon, and mesenteric tissues were sampled for AIEC quantification and evaluation of inflammation. RESULTS: Without antibiotic treatment, AIEC was not able to colonize WT and NOD2KO mice. Compared with nontreated animals, antibiotic treatment led to a significant increase in ileal and colonic colonization of AIEC in WT and/or NOD2KO mice. Persistent AIEC colonization was observed until day 5 only in NOD2KO mice, disappearing at day 60. Mesenteric translocation of AIEC was observed only in NOD2KO mice. No inflammation was observed in WT and NOD2KO mice treated with antibiotics and infected with AIEC. During DSS-induced colitis, colonization and persistence of AIEC was observed in the colon. Moreover, a dramatic increase in clinical, histological, and molecular parameters of colitis was observed in mice infected with AIEC but not with a commensal E. coli strain. CONCLUSIONS: Antibiotic treatment was necessary for AIEC colonization of the gut and mesenteric tissues and persistence of AIEC was dependent on NOD2. AIEC exacerbated a preexisting DSS-induced colitis in WT mice. (Inflamm Bowel Dis 2012;).
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2.60Impact points
Visceral fat and gut inflammation.
Nutrition (Burbank, Los Angeles County, Calif.). 02/2012; 28(2):113-7.
The etiology of inflammatory bowel disease and, in particular, Crohn's disease involves a deregulated mucosal immune system under the influence of intestinal flora and environmental factors in genetically susceptible individuals. A new hypothesis has focused on mesenteric fat hypertrophy and the... [more] The etiology of inflammatory bowel disease and, in particular, Crohn's disease involves a deregulated mucosal immune system under the influence of intestinal flora and environmental factors in genetically susceptible individuals. A new hypothesis has focused on mesenteric fat hypertrophy and the presence of ectopic fat surrounding inflamed bowel, the so-called creeping fat, which are hallmarks of Crohn's disease. Mesenteric adipose tissue is currently recognized as an active actor in immunity with a capacity for mediator secretion. These mediators include classic pro- and anti-inflammatory cytokines or chemokines and hormone-like adipokines with multiple effects. Mesenteric fat participates in the course of Crohn's disease and may play an active role in the regulation of intestinal inflammation. However, little is known about the origin and role of mesenteric fat in Crohn's disease, essentially because of a lack of experimental models that develop creeping fat. The purpose of this review is to present the recent data describing the immune properties of mesenteric fat and the recent advances in animal models, which have suggested a new hypothesis about the role of creeping fat in Crohn's disease.
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9.36Impact points
Mesenteric fat as a source of C reactive protein and as a target for bacterial translocation in Crohn's disease.
Gut. 09/2011; 61(1):78-85.
Objective: Mesenteric fat hyperplasia is a hallmark of Crohn's disease (CD), and C reactive protein (CRP) is correlated with disease activity. The authors investigated whether mesenteric adipocytes may be a source of CRP in CD and whether inflammatory and bacterial triggers may stimulate its pro... [more] Objective: Mesenteric fat hyperplasia is a hallmark of Crohn's disease (CD), and C reactive protein (CRP) is correlated with disease activity. The authors investigated whether mesenteric adipocytes may be a source of CRP in CD and whether inflammatory and bacterial triggers may stimulate its production by adipocytes. CRP expression in the mesenteric and subcutaneous fats of patients with CD and the correlation between CRP plasma concentrations and mesenteric messenger RNA (mRNA) levels were assessed. The impact of inflammatory and bacterial challenges on CRP synthesis was tested using an adipocyte cell line. Bacterial translocation to mesenteric fat was studied in experimental models of colitis and ileitis and in patients with CD. CRP expression was increased in the mesenteric fat of patients with CD, with mRNA levels being 80 ± 40 (p<0.05) and 140 ± 65 (p=0.04) times higher than in the mesenteric fat of patients with ulcerative colitis and in the subcutaneous fat of the same CD subjects, respectively, and correlated with plasma levels. Escherichia coli (1230 ± 175-fold, p<0.01), lipopolysaccharide (26 ± 0.5-fold, p<0.01), tumour necrosis factor α (15 ± 0.3-fold, p<0.01) and interleukin-6 (10 ± 0.7-fold, p<0.05) increased CRP mRNA levels in adipocyte 3T3-L1 cells. Bacterial translocation to mesenteric fat occurred in 13% and 27% of healthy and CD subjects, respectively, and was increased in experimental colitis and ileitis. Human mesenteric adipocytes constitutively expressed mRNA for TLR2, TLR4, NOD1 and NOD2. Mesenteric fat is an important source of CRP in CD. CRP production by mesenteric adipocytes may be triggered by local inflammation and bacterial translocation to mesenteric fat, providing a mechanism whereby mesenteric fat hyperplasia may contribute to inflammatory response in CD.
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4.36Impact points
Increased lymphatic vessel density and lymphangiogenesis in inflammatory bowel disease.
Alimentary pharmacology & therapeutics. 09/2011; 34(5):533-43.
Involvement of the lymphatic system in inflammatory bowel disease (IBD) has been suggested. To examine the density and distribution of lymphatic vessels (LV) within inflamed and non-inflamed wall sections of IBD patients compared with controls, and to evaluate expression of major lymphangiogenic fac... [more] Involvement of the lymphatic system in inflammatory bowel disease (IBD) has been suggested. To examine the density and distribution of lymphatic vessels (LV) within inflamed and non-inflamed wall sections of IBD patients compared with controls, and to evaluate expression of major lymphangiogenic factors. Ileal and colon specimens of 22 patients with Crohn's disease (CD), 16 patients with ulcerative colitis (UC) and 11 controls were studied. Quantification of LV was performed using immunohistochemistry with podoplanin and D2-40 antibodies on seven randomly selected fields. Mucosal expression of podoplanin and lymphangiogenic factor mRNA was measured using PCR. In CD patients, lymphatic density was significantly increased in non-inflamed and inflamed ileal (P < 0.01 and P < 0.001) and colonic (P < 0.01 and P < 0.001) mucosa compared to controls. Podoplanin mRNA levels were similar in non-inflamed mucosal areas and controls, whereas a four- and sixfold increase was seen in inflamed ileal and colonic areas (P < 0.05). In UC, lymphatic density increased fourfold in non-inflamed (P < 0.001) and fivefold in inflamed colonic mucosa (P < 0.001) compared with controls. An increase in podoplanin mRNA levels was seen in both non-inflamed and inflamed areas (P < 0.01) compared with controls. In CD and UC, lymphatics were found throughout the inflamed mucosa, including the upper half of the lamina propria. Expression of lymphangiogenic factors was similar in patients and controls. Increased density of lymphatic vessels is a constant feature of IBD and is present in non-inflamed areas. It is transmural in CD and confined to the mucosa in UC. Its origin remains unclear.
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4.64Impact points
Trough levels and antibodies to infliximab may not predict response to intensification of infliximab therapy in patients with inflammatory bowel disease.
Inflammatory bowel diseases. 08/2011;
BACKGROUND: Infliximab is effective for the treatment of refractory inflammatory bowel disease (IBD). Nevertheless, up to 40% of patients lose response to infliximab over time. The aim was to assess the clinical value of measuring infliximab trough levels and antibodies to infliximab (ATI) concentra... [more] BACKGROUND: Infliximab is effective for the treatment of refractory inflammatory bowel disease (IBD). Nevertheless, up to 40% of patients lose response to infliximab over time. The aim was to assess the clinical value of measuring infliximab trough levels and antibodies to infliximab (ATI) concentrations in IBD patients who lost response to infliximab therapy. METHODS: We retrospectively studied records of IBD patients who lost response to infliximab therapy. We first assessed clinical responses of different therapeutic strategies that were applied when patients lost response to infliximab and then we looked at the correlation between clinical response and infliximab trough levels and ATI concentrations. RESULTS: Seventy-six IBD patients were included. 31/76 patients (41%) continued infliximab therapy without any modification, 39 patients (51%) had an intensification of infliximab therapy, five patients (7%) had switched to adalimumab therapy, and one patient (1%) underwent surgery. Clinical response was observed in 27 patients (69%) with an intensification of infliximab therapy. There was no significant difference in mean infliximab trough level at inclusion in patients who responded to intensification of infliximab therapy (3.3 ± 4.1 μg/mL) as compared with patients who did not respond (2.3 ± 2.2 μg/mL, P = 0.85). In all, 16/76 patients (22.4%) presented detectable ATI in the serum. Ten ATI-positive patients had an intensification of infliximab therapy and six (60%) demonstrated a clinical response. After intensification of infliximab therapy the ATI concentration decreased in five patients. CONCLUSIONS: In patients with IBD who lose response to infliximab, clinical improvement may occur upon intensification of infliximab therapy, irrespective of infliximab serum concentration or presence of ATI. (Inflamm Bowel Dis 2011;).
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5.64Impact points
Natural history of eosinophilic gastroenteritis.
Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association. 07/2011; 9(11):950-956.e1.
Eosinophilic gastroenteritis (EGE) is a rare gastrointestinal disorder; little is known about its natural history. We determined the clinical features and long-term outcomes of patients with EGE. We reviewed files from 43 patients diagnosed with EGE who were followed from January 1988 to April 2009.... [more] Eosinophilic gastroenteritis (EGE) is a rare gastrointestinal disorder; little is known about its natural history. We determined the clinical features and long-term outcomes of patients with EGE. We reviewed files from 43 patients diagnosed with EGE who were followed from January 1988 to April 2009. The diagnosis was made according to standard criteria after other eosinophilic gastrointestinal disorders were excluded. We analyzed data on initial clinical presentation and long-term outcomes. EGE was classified as mucosal, subserosal, or muscular in 44%, 39%, and 12% of cases, respectively. Disease location was mostly duodenal (62%), ileal (72%), or colonic (88%); it was less frequently esophageal (30%) or gastric (38%). Blood eosinophilia (numbers >500/mm(3)) was observed in 74% of cases. Spontaneous remission occurred in 40% of patients; the majority of treated patients (74%) received oral corticosteroids, which were effective in most cases. After a median follow-up period of 13 years (0.8-29 years), we identified 3 different courses of disease progression: 18 patients (42%; 9 with subserosal disease) had an initial flare of the disease without relapse, 16 (37%) had multiple flares that were separated by periods of full remission (recurring disease), and 9 (21%) had chronic disease. The clinical presentation of EGE is heterogeneous and varies in histologic pattern; about 40% of patients resolve the disease spontaneously, without relapse. Approximately 50% have a more complex disease, which is characterized by unpredictable relapses and a chronic course.
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4.64Impact points
Variants of NOD1 and NOD2 genes display opposite associations with familial risk of crohn's disease and anti-saccharomyces cerevisiae antibody levels.
Inflammatory bowel diseases. 07/2011; 18(3):430-8.
NOD2 is involved in Crohn's disease (CD), but the role of NOD1 remains unclear. Anti-Saccharomyces cerevisiae antibodies (ASCA) are higher in CD patients and some of their relatives. Using family-based analyses we investigated the relationships between NOD2 mutations, NOD1 +32656 variant, and bo... [more] NOD2 is involved in Crohn's disease (CD), but the role of NOD1 remains unclear. Anti-Saccharomyces cerevisiae antibodies (ASCA) are higher in CD patients and some of their relatives. Using family-based analyses we investigated the relationships between NOD2 mutations, NOD1 +32656 variant, and both the risk of CD and ASCA levels. We compared allelic frequencies between families with multiple CD cases (multiplex), those with one case of CD (simplex), and control families, searching for a gradient of at risk alleles according to the prevalence of the disease among families. In all, 93 CD patients, 160 healthy relatives from 22 multiplex families, 22 CD patients and 81 healthy relatives from 22 simplex families, and 169 subjects from 27 control families were included in the study. ASCA levels were determined by enzyme-linked immunosorbent assay. NOD1 +32656, NOD2 R702W, G908R, and 1007fs were genotyped by polymerase chain reaction / restriction fragment length polymorphism. In family-based analyses NOD2 mutations and the NOD1 wildtype allele were associated with CD in multiplex families, with a synergetic effect when risk alleles of both genes were transmitted. Lower ASCA levels were strongly associated with the NOD1 variant allele. Simplex families had a lower frequency of the "at risk" +32656 allele than multiplex families. The +32656 variant was associated with low ASCA level and low risk of CD in multiplex families. NOD2 and NOD1 variants displayed antagonist effects on the risk of CD and ASCA level. A gradient of NOD1, NOD2 at-risk alleles was associated with the variable prevalence of CD in families. (Inflamm Bowel Dis 2012;).
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2.82Impact points
New FAAH inhibitors based on 3-carboxamido-5-aryl-isoxazole scaffold that protect against experimental colitis.
Bioorganic & medicinal chemistry. 06/2011; 19(12):3777-86.
Growing evidence suggests a role for the endocannabinoid (EC) system, in intestinal inflammation and compounds inhibiting anandamide degradation offer a promising therapeutic option for the treatment of inflammatory bowel diseases. In this paper, we report the first series of carboxamides derivative... [more] Growing evidence suggests a role for the endocannabinoid (EC) system, in intestinal inflammation and compounds inhibiting anandamide degradation offer a promising therapeutic option for the treatment of inflammatory bowel diseases. In this paper, we report the first series of carboxamides derivatives possessing FAAH inhibitory activities. Among them, compound 39 displayed significant inhibitory FAAH activity (IC(50)=0.088 μM) and reduced colitis induced by intrarectal administration of TNBS.
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Enzymatically degraded Eurylon 6 HP-PG: ethylcellulose film coatings for colon targeting in inflammatory bowel disease patients.
The Journal of pharmacy and pharmacology. 12/2010; 62(12):1676-84.
Film coatings based on blends of Eurylon 6 HP-PG (a hydroxypropylated and pregelatinized high amylose starch) and ethylcellulose were to be evaluated as promising coating materials for site-specific drug delivery to the colon of patients suffering from inflammatory bowel diseases. Pellet starter cor... [more] Film coatings based on blends of Eurylon 6 HP-PG (a hydroxypropylated and pregelatinized high amylose starch) and ethylcellulose were to be evaluated as promising coating materials for site-specific drug delivery to the colon of patients suffering from inflammatory bowel diseases. Pellet starter cores containing 60% 5-aminosalicylic acid were prepared by extrusion/spheronization and coated with different Eurylon 6 HP-PG:ethylcellulose blends at various coating levels. Drug release was measured in media simulating the contents of the upper gastrointestinal tract (in the presence and absence of enzymes) as well as in media simulating the contents of the colon. 5-Aminosalicylic acid release could effectively be suppressed in 0.1 N HCl and phosphate buffer pH 6.8, optionally containing pepsin or pancreatin, but occurred as soon as the pellets came into contact with culture medium inoculated with faecal samples from inflammatory bowel disease patients. This can be attributed to the partial degradation of the starch derivative by enzymes secreted by bacteria present in the colon of these patients. The presented drug delivery system is adapted to the pathophysiological conditions in inflammatory bowel disease patients. Furthermore, drug release remained unaltered upon 1 year open storage.
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4.80Impact points
4-Oxo-1,4-dihydropyridines as selective CB2 cannabinoid receptor ligands: structural insights into the design of a novel inverse agonist series.
Journal of medicinal chemistry. 10/2010; 53(22):7918-31.
Growing evidence shows that CB(2) receptor is an attractive therapeutic target. Starting from a series of 4-oxo-1,4-dihydroquinoline-3-carboxamide as selective CB(2) agonists, we describe here the medicinal chemistry approach leading to the development of CB(2) receptor inverse agonists with a 4-oxo... [more] Growing evidence shows that CB(2) receptor is an attractive therapeutic target. Starting from a series of 4-oxo-1,4-dihydroquinoline-3-carboxamide as selective CB(2) agonists, we describe here the medicinal chemistry approach leading to the development of CB(2) receptor inverse agonists with a 4-oxo-1,4-dihydropyridine scaffold. The compounds reported here show high affinity and potency at the CB(2) receptor while showing only modest affinity for the centrally expressed CB(1) cannabinoid receptor. Further, we found that the functionality of this series is controlled by its C-6 substituent because agonists bear a methyl or a tert-butyl group and inverse agonists, a phenyl or 4-chlorophenyl group, respectively. Finally, in silico studies suggest that the C-6 substituent could modulate the conformation of W6.48 known to be critical in GPCR activation.
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Obesity, visceral fat and Crohn's disease.
Current opinion in clinical nutrition and metabolic care. 09/2010; 13(5):574-80.
Increasing evidence indicates that adipose tissue is an active endocrine organ involved in metabolic syndrome and regulation of inflammation. Visceral fat accumulation is a hallmark of both obesity and Crohn's disease. Here, we present recent data describing the immune properties of intra-abdomi... [more] Increasing evidence indicates that adipose tissue is an active endocrine organ involved in metabolic syndrome and regulation of inflammation. Visceral fat accumulation is a hallmark of both obesity and Crohn's disease. Here, we present recent data describing the immune properties of intra-abdominal adipose tissue that could link the innate immune response to obesity-related disorders and gut inflammation. Innate immune properties of adipocytes have become well characterized since recent studies described the Toll-like receptor (TLR) expression repertoire and specific TLR ligand responses of adipocytes. Adipokine secretion profiles have also been elucidated both in obese patients, when they may be involved in obesity-associated metabolic disease, and in Crohn's disease. Whereas mesenteric fat hypertrophy and fat wrapping of the bowel are characteristic of Crohn's disease, there exists a paucity of information concerning this important pathophysiological aspect. Our current classical animal models are of limited interest when investigating the role of mesenteric fat in gut inflammation. Recent new alternative disease paradigms could help to design more specific models for elucidating chronic transmural inflammation of the gut. Obesity and Crohn's disease share common features with the development of mesenteric fat that may be involved in gut inflammation. Further studies are required to clearly assess the origin and influence of intestinal fat deposits upon gut inflammation, notably during Crohn's disease development.
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9.43Impact points
Peroxisome proliferator-activated receptor gamma activation is required for maintenance of innate antimicrobial immunity in the colon.
Proceedings of the National Academy of Sciences of the United States of America. 05/2010; 107(19):8772-7.
Crohn's disease (CD), a major form of human inflammatory bowel disease, is characterized by primary immunodeficiencies. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma) is essential for intestinal homeostasis in response to both dietary- and microbiota-derived si... [more] Crohn's disease (CD), a major form of human inflammatory bowel disease, is characterized by primary immunodeficiencies. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma) is essential for intestinal homeostasis in response to both dietary- and microbiota-derived signals. Its role in host defense remains unknown, however. We show that PPARgamma functions as an antimicrobial factor by maintaining constitutive epithelial expression of a subset of beta-defensin in the colon, which includes mDefB10 in mice and DEFB1 in humans. Colonic mucosa of Ppargamma mutant animals shows defective killing of several major components of the intestinal microbiota, including Candida albicans, Bacteroides fragilis, Enterococcus faecalis, and Escherichia coli. Neutralization of the colicidal activity using an anti-mDefB10 blocking antibody was effective in a PPARgamma-dependent manner. A functional promoter variant that is required for DEFB1 expression confers strong protection against Crohn's colitis and ileocolitis (odds ratio, 0.559; P = 0.018). Consistently, colonic involvement in CD is specifically linked to reduced expression of DEFB1 independent of inflammation. These findings support the development of PPARgamma-targeting therapeutic and/or nutritional approaches to prevent colonic inflammation by restoring antimicrobial immunity in CD.
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12.90Impact points
Neutrophil migration during liver injury is under nucleotide-binding oligomerization domain 1 control.
Gastroenterology. 12/2009;
BACKGROUND & AIMS:: A more complete understanding of the mechanisms involved in pathogen-associated molecular pattern signalling is crucial in the setting of liver injury. In intestinal diseases, nucleotide-binding oligomerization domain1 (NOD1), a receptor for bacteria, appears to regulate cros... [more] BACKGROUND & AIMS:: A more complete understanding of the mechanisms involved in pathogen-associated molecular pattern signalling is crucial in the setting of liver injury. In intestinal diseases, nucleotide-binding oligomerization domain1 (NOD1), a receptor for bacteria, appears to regulate cross-talk between innate and adaptive immunity, involving polymorphonuclear neutrophils (PMNs). Our aim was to explore the role of NOD1 in PMN-induced liver injury. METHODS:: Nod1(+/+) and Nod1(-/-) mice were challenged with CCl(4). Migration and phagocytosis of Nod1(+/+) and Nod1(-/-) PMN were studied in and ex-vivo. We evaluated main inflammatory pathways in PMN by western-blot and CD11b expression using FACS analysis. Mice were submitted to the ischemia/reperfusion (I/R) model. RESULTS:: In liver injury model following CCl(4) exposure, livers of Nod1(-/-) mice had over 50% less PMN infiltration within necrotic areas than those of Nod1(+/+). PMNs isolated from Nod1(-/-) mice displayed a 90% decrease in migration capacity compared to Nod1(+/+) PMNs, whereas FK565, a potent NOD1 ligand, significantly increased PMN migration. Upon FK565 and fMLP stimulation, MAPK and NF-kappaB were activated in Nod1(+/+) PMNs, but less so in Nod1(-/-) PMNs. Expression of CD11b on the Nod1(-/-) PMN surface was significantly decreased compared to Nod1(+/+). The phagocytic capacity of Nod1(-/-) PMN was decreased by more than 50% compared to Nod1(+/+). In a I/R model of PMN-induced liver injury, FK565 increased lesions, whereas Nod1(-/-) mice were protected. CONCLUSIONS:: First identification of NOD1 as modulator of PMN function and migration in the liver suggest that this receptor may represent a new therapeutic target in PMN-dependent liver diseases.
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2.61Impact points
Novel polymeric film coatings for colon targeting: Drug release from coated pellets.
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences. 07/2009; 37(3-4):427-33.
The aim of this study was to prepare and characterize novel types of polymer coated pellets allowing for the site-specific delivery of drugs to the colon. 5-Aminosalicylic acid (5-ASA)-loaded beads were prepared by extrusion-spheronization and coated with different Nutriose:ethylcellulose blends. In... [more] The aim of this study was to prepare and characterize novel types of polymer coated pellets allowing for the site-specific delivery of drugs to the colon. 5-Aminosalicylic acid (5-ASA)-loaded beads were prepared by extrusion-spheronization and coated with different Nutriose:ethylcellulose blends. In vitro drug release from these systems was measured under various conditions, including the exposure to fresh fecal samples from inflammatory bowel disease patients under anaerobic conditions. Nutriose is a starch derivative, which is preferentially degraded by enzymes secreted by the microflora in the colon of Crohn's disease and ulcerative colitis patients. Interestingly, the release of 5-ASA (which is commonly used for the local treatment of inflammatory bowel diseases) could effectively be suppressed upon exposure to release media simulating the conditions in the upper GIT, irrespective of the degree of agitation and presence or absence of enzymes. But as soon as the pellets came into contact with fecal samples of inflammatory bowel disease patients, the release rate significantly increased and the drug was released in a time-controlled manner. Thus, this novel type of colon targeting system is adapted to the pathophysiology of the patient. Furthermore, culture media containing specific colonic bacteria are presented providing an interesting potential as substitutes for fresh fecal samples.
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0.96Impact points
Characterization of ethylcellulose: starch-based film coatings for colon targeting.
Drug development and industrial pharmacy. 06/2009;
Background: The site-specific delivery of drugs to the colon can be highly advantageous for various applications, including the local treatment of inflammatory bowel diseases. The aim of this study was to provide efficient tools that can be used to easily adjust the key properties of novel polymeric... [more] Background: The site-specific delivery of drugs to the colon can be highly advantageous for various applications, including the local treatment of inflammatory bowel diseases. The aim of this study was to provide efficient tools that can be used to easily adjust the key properties of novel polymeric film coatings allowing for colon targeting. Methods: Free films based on blends of ethylcellulose and different types of starch derivatives (partially being pregelatinized, acetylated, and/or hydroxypropylated) were prepared and characterized. Results: The key properties of the polymeric systems can effectively be adjusted by varying the polymer blend ratio and type of starch derivative. This includes the water uptake and dry mass loss kinetics as well as the mechanical properties of the films before and upon exposure to aqueous media simulating the contents of the upper GIT. Conclusion: Broad ranges of film coating properties can easily be provided, being adapted to the needs of the respective drug treatment.
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3.15Impact points
Colon targeting with bacteria-sensitive films adapted to the disease state.
European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V. 06/2009;
The aim of this study was to identify novel polymeric films allowing for the site-specific delivery of drugs to the colon of patients suffering from inflammatory bowel diseases. Ethylcellulose was blended with different types of bacteria-sensitive starch derivatives. The water uptake and dry mass lo... [more] The aim of this study was to identify novel polymeric films allowing for the site-specific delivery of drugs to the colon of patients suffering from inflammatory bowel diseases. Ethylcellulose was blended with different types of bacteria-sensitive starch derivatives. The water uptake and dry mass loss kinetics of the systems were monitored upon exposure to media simulating the contents of the stomach, small intestine and colon (including fresh fecal samples from Crohn's Disease and Ulcerative Colitis patients). Importantly, ethylcellulose:Nutriose FB 06 and ethylcellulose:Peas starch N-735 films showed highly promising water uptake and dry mass loss kinetics in all the investigated media, indicating their potential to minimize premature drug release in the upper gastro-intestinal tract, and allowing for controlled release once the colon is reached. This can be attributed to the fact that the starch derivatives serve as substrates for the enzymes, which are secreted by the bacteria present in the colon of inflammatory bowel disease patients. Thus, the identified new polymeric films are adapted to the pathophysiological conditions in the gastro-intestinal tract in the disease state. Furthermore, Nutriose is known to provide pre-biotic effects, which can be of great benefit for these patients.
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4.64Impact points
Effects of infliximab therapy on abdominal fat and metabolic profile in patients with Crohn's disease.
Inflammatory bowel diseases. 03/2009;
BACKGROUND:: Tumor necrosis factor is an adipocytokine possessing a well-established lipolytic effect. In Crohn's disease (CD) patients, infliximab therapy may thus result in visceral fat accumulation, which is associated with an increased risk of metabolic syndrome. METHODS:: A total of 132 CD ... [more] BACKGROUND:: Tumor necrosis factor is an adipocytokine possessing a well-established lipolytic effect. In Crohn's disease (CD) patients, infliximab therapy may thus result in visceral fat accumulation, which is associated with an increased risk of metabolic syndrome. METHODS:: A total of 132 CD patients were investigated. In a first prospective study, magnetic resonance imaging (MRI) quantification of subcutaneous and visceral abdominal fat was performed before and 8 weeks after initiation of infliximab induction therapy (5 mg/kg at weeks 0, 2, and 6) in 21 responding patients treated for perianal disease. In a second prospective study, fasting glycemia, glycated hemoglobin (HbA1c), HDL, LDL, and total cholesterol and triglyceride levels were assessed in 111 responding patients receiving infliximab infusions every 8 weeks, with a mean follow-up of 41 weeks. RESULTS:: A significant homogeneous 18% increase in total abdominal fat was observed in the 21 CD patients after infliximab induction therapy (P = 0.027), independently of body mass index evolution. Infliximab maintenance therapy was associated with a decrease in glycemia (P < 0.0001) and HbA1c (P = 0.0005) concentrations, together with an increase in both total cholesterol (P = 0.02) and HDL cholesterol (P = 0.008) concentrations. All glycemic and lipid parameters remained within the normal range throughout the study. CONCLUSIONS:: Infliximab induction therapy is associated with a significant increase in abdominal fat tissue in CD patients. Infliximab maintenance therapy has no deleterious effects on lipid profile and is accompanied by a decrease in glycemia and HbA1c concentrations, probably by reversing the impairment of tumor necrosis factor-induced insulin-mediated glucose uptake. (Inflamm Bowel Dis 2009;).
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2.96Impact points
Novel polymeric film coatings for colon targeting: How to adjust desired membrane properties.
International journal of pharmaceutics. 01/2009;
The major aim of this work was to optimize the properties of novel polymeric films based on blends of ethylcellulose and Nutriose (a water-soluble, branched dextrin). Such blends were recently shown to be highly promising for the site-specific delivery of drugs to the colon in patients suffering fro... [more] The major aim of this work was to optimize the properties of novel polymeric films based on blends of ethylcellulose and Nutriose (a water-soluble, branched dextrin). Such blends were recently shown to be highly promising for the site-specific delivery of drugs to the colon in patients suffering from inflammatory bowel diseases, in particular Crohn's disease and ulcerative colitis. Importantly, and in contrast to various other colon targeting approaches, the system is adapted to the pathophysiological conditions in the disease state. However, it is yet unknown how desired membrane properties, especially water uptake and dry mass loss kinetics as well as mechanical stability can be adjusted to the specific needs of particular drug treatments. Different highly efficient and easy to apply tools were identified altering the membrane's properties, in particular their mechanical resistance required to withstand the shear forces resulting from the motility of the upper GIT and the hydrostatic pressure built up within the devices upon contact with aqueous media. This includes the variation of the Nutriose:ethylcellulose blend ratio and initial plasticizer content. Importantly, Nutriose also exhibits significant pre-biotic activity, normalizing the microflora in the patients' colon, which is of major clinical benefit in the case of inflammatory bowel diseases.
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0.71Impact points
Occupational exposure to ambient electromagnetic fields of technical operational personnel working for a mobile telephone operator.
Radiation protection dosimetry. 01/2009; 136(3):185-95.
In order to investigate the exposure of operational personnel to radiofrequency electromagnetic fields when working for a mobile telephone operator, exposimeters were used to make individual records on 23 Technical Operations personnel (mobile telephone maintenance staff) and also on 22 Other Worker... [more] In order to investigate the exposure of operational personnel to radiofrequency electromagnetic fields when working for a mobile telephone operator, exposimeters were used to make individual records on 23 Technical Operations personnel (mobile telephone maintenance staff) and also on 22 Other Workers. The exposure densities, to which each of the 45 subjects was subjected, were quantified using 229 exposure indicators. Cluster analysis techniques were applied to the data, in an attempt to show that they would re-emerge as belonging to one of the two groups, i.e. the Technical Operational Personnel group or the Other Workers group. This exploratory investigation has shown that the cluster analysis does not reveal a sufficiently reliable emergence of the two groups, even though certain exposure indicators were significantly different for the two groups. In addition, the use of a Learning Group method does not lead to the discovery of a predictive law that could identify the Technical Operational Personnel as a sub-group within the overall group.
Following (21)
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Harald Peeters
University of Ghent -
Didier M Lambert
University of Louvain -
David Dombrowicz
Institut national de la santé et de la recherche médicale -
Francis Vasseur
Université du Droit et de la Santé Lille 2 -
Philippe Seksik
Assistance Publique – Hôpitaux de Paris
Topics (1)
