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Biomedical subjects

Sander J H van Deventer

Publications and source records attributed to Sander J H van Deventer.

At least 19 recordsLinked to original sources

Comparative analysis of colonic gene expression of three experimental colitis models mimicking inflammatory bowel disease.

BACKGROUND: Mouse models of inflammatory bowel diseases (IBD) are used to unravel the pathophysiology of IBD and to study new treatment modalities, but their relationship to Crohn's disease (CD) or ulcerative colitis (UC) is speculative. METHODS: Using Agilent mouse TOX oligonucleotide microarrays, we analyzed colonic gene expression profiles in three widely used models of experimental colitis. In 2 of the models (TNBS and DSS-induced colitis), exogenous agents induce the colitis. In the third model the colitis is induced after transfer of a T-cell population (CD4(+)CD45RB(high) T cells) that lacks regulatory cells into an immunodeficient host. RESULTS: Compared with control mice, in DSS, TNBS, and the CD45RB transfer colitis mice, 387, 21, and 582 genes were more than 2-fold upregulated in the intestinal mucosa. Analyses of exclusively shared gene expression profiles between the different models revealed that DSS/transfer colitis share 69 concordantly upregulated genes, DSS/TNBS 6, and TNBS/transfer colitis 1. Seven genes were upregulated in all three models. The CD45RB transfer model expression profile included the most genes that are known to be upregulated in IBD. Of 32 genes that are known to change transcriptional activity in IBD (TNF, IFN-gamma, Ltbeta, IL-6, IL-16, IL-18R1, IL-22, CCR2, 7, CCL2, 3, 4, 5, 7, 11, 17, 20, CXCR3, CXCL1, 5, 10, Mmp3, 7,9, 14, Timp1, Reg3gamma, and Pap, S-100a8, S-100a9, Abcb1, and Ptgs2), 2/32 are upregulated in TNBS, 15/32 are upregulated or downregulated in DSS and 30/32 are upregulated or downregulated in the CD45RB transfer colitis. CONCLUSION: The pattern of gene expression in the CD45RB transfer model most closely reflects altered gene expression in IBD.

Animals↗

Prediction of antitumour necrosis factor clinical efficacy by real-time visualisation of apoptosis in patients with Crohn's disease.

BACKGROUND: The human anti-tumour necrosis factor (TNF) antibody infliximab binds to the membrane TNF and subsequently induces apoptosis of activated lamina propria T lymphocytes in patients with Crohn's disease in vitro. AIM: To test whether the ability of rapid anti-TNF-induced apoptosis in the gut predicts the efficacy of anti-TNF treatment in inflammatory bowel disease. METHODS: (99m)Technetium-annexin V single-photon emission computer tomography (SPECT) was performed in 2 models of murine experimental colitis and in 14 patients with active Crohn's disease as assessed by the Crohńs Disease Activity Index (CDAI) to study the effect of anti-TNF treatment on apoptosis in the intestine during active colitis. Disease activity was evaluated 2 weeks after infliximab infusion using the CDAI (definition response: drop of >100 points). RESULTS: Colonic uptake of (99m)Tc-annexin V significantly increased in 2,4,6-trinitrobenzene sulphonate-induced colitis as well as in transfer colitis on administration of anti-TNF antibodies compared with a control antibody as determined with dedicated animal pinhole SPECT. In addition, uptake of (99m)Tc-annexin V significantly increased in patients with active Crohn's disease responding to infliximab treatment. Colonic (99m)Tc-annexin V uptake ratio (mean (SEM)) increased from 0.24 (0.03) to 0.41(0.07) (p<0.01), 24 h after infliximab infusion (5 mg/kg). A mean increase of 98.7% in colonic uptake of (99m)Tc-annexin V could be detected in 10 of the 14 responding patients (CDAI >100 points at week 2) compared with 15.2% in non-responding patients (p = 0.03). Analysis of the mucosal biopsy specimens identified lamina propria T cells as target cells undergoing apoptosis. CONCLUSIONS: These in vivo observations support the notion that colonic uptake of (99m)Tc-annexin V correlates with clinical benefit of anti-TNF treatment and might be predictive of therapeutic success.

Adult↗

Treatment and prevention of Staphylococcus epidermidis experimental biomaterial-associated infection by bactericidal peptide 2.

Biomaterial-associated infections (BAI) are the major cause of failure of indwelling medical devices and are predominantly caused by staphylococci, especially Staphylococcus epidermidis. We investigated the in vitro microbicidal activity of the synthetic antimicrobial peptide bactericidal peptide 2 (BP2) and its efficacy in a murine model of S. epidermidis BAI. BP2 showed potent microbicidal activity at micromolar concentrations against a broad spectrum of microorganisms, including antibiotic-resistant bacteria. The staphylocidal activity of BP2 was not affected by physiological salt concentrations and was only slightly affected by the presence of human plasma. In the BAI model, injection of BP2 (5 mg/kg of body weight) 1 h after challenge with S. epidermidis resulted in an 80% reduction in the number of culture-positive implants and a 100-fold reduction in survival of S. epidermidis in peri-implant tissue at 24 h postchallenge. When BP2 was injected along implants 3 h prior to bacterial challenge, the median numbers of CFU cultured from biomaterial implants and peri-implant tissue were reduced by 85% and 90%, respectively. In conclusion, BP2 has potent, broad-spectrum in vitro microbicidal activity and showed potent in vivo activity in a murine model of S. epidermidis biomaterial-associated infection.

Animals↗

A phase I trial with transgenic bacteria expressing interleukin-10 in Crohn's disease.

BACKGROUND & AIMS: The use of living, genetically modified bacteria is an effective approach for topical delivery of immunomodulatory proteins. This strategy circumvents systemic side effects and allows long-term treatment of chronic diseases. However, treatment of patients with a living, genetically modified bacterium raises questions about the safety for human subjects per se and the biologic containment of the transgene. METHODS: We treated Crohn's disease patients with genetically modified Lactococcus lactis (LL-Thy12) in which the thymidylate synthase gene was replaced with a synthetic sequence encoding mature human interleukin-10. Ten patients were included in a placebo-uncontrolled trial. Patients were assessed daily for the presence of potential adverse effects by direct questioning and assessment of disease activity. We evaluated the presence and kinetics of LL-Thy12 release in the stool of patients by conventional culturing and quantitative polymerase chain reaction of LL-Thy12 gene sequences. RESULTS: Treatment with LL-Thy12 was safe because only minor adverse events were present, and a decrease in disease activity was observed. Moreover, fecally recovered LL-Thy12 bacteria were dependent on thymidine for growth and interleukin-10 production, indicating that the containment strategy was effective. CONCLUSIONS: Here we show that the use of genetically modified bacteria for mucosal delivery of proteins is a feasible strategy in human beings. This novel strategy avoids systemic side effects and is biologically contained; therefore it is suitable as maintenance treatment for chronic intestinal disease.

C-Reactive Protein↗

Inosine triphosphate pyrophosphatase and thiopurine s-methyltransferase genotypes relationship to azathioprine-induced myelosuppression.

BACKGROUND & AIMS: The use of azathioprine (AZA) in inflammatory bowel disease (IBD) patients is limited by toxicity, which occurs in up to 20% of treated patients. Mutations in the thiopurine S-methyltransferase (TPMT) and inosine triphosphate pyrophosphatase (ITPA) genes have been associated with the occurrence of AZA-related toxicity. The aim of our study was to determine the relative contribution of ITPA and TPMT mutations to the development of toxicity induced by AZA treatment in IBD patients. METHODS: ITPA(94C>A, IVS2+21A>C) and TPMT (238G>C, 460G>A, and 719A>G) genotypes were assessed in 262 IBD patients (159 females, 103 males; 67 patients with ulcerative colitis, 195 patients with Crohn's disease) treated with AZA and were correlated with the development of leukopenia and hepatotoxicity. RESULTS: Leukopenia (leukocyte count, <3.0 x 10(9)/L) was observed in 4.6% of treated patients. The frequencies of mutant ITPA 94C>A and TPMT alleles were significantly higher in the leukopenic population compared with patients without leukopenia (16.7% and 5.4%, respectively, for ITPA 94C>A, and 20.8% and 4%, respectively, for TPMT). Moreover, the ITPA 94C>A and TPMT mutations predicted leukopenia: ITPA 94C>A odds ratio, 3.504; 95% confidence interval, 1.119-10.971 (P = .046); TPMT odds ratio, 6.316; 95% confidence interval, 2.141-18.634 (P = .004). Neither TPMT nor ITPA genotype predicted hepatotoxicity. CONCLUSIONS: ITPA 94C>A and TPMT polymorphisms are associated with AZA-related leukopenia in IBD patients.

Adolescent↗

Pharmacokinetics of 6-thioguanine in patients with inflammatory bowel disease.

6-Thioguanine (6-TG) seems to be an attractive alternative in both AZA- and 6-MP-intolerant and -resistant IBD populations. However, little is known of 6-TG pharmacokinetics, metabolite levels, and their correlation with drug efficacy and toxicity in IBD patients. This study reports the 6-TG pharmacokinetics in a population of IBD patients and the predictive value of metabolite concentrations. Red blood cell (RBC) 6-thioguanine nucleotide (6-TGN) concentrations were measured in 28 IBD patients at t = 1, 2, 4, and 8 weeks after starting 6-TG, 20 mg once daily. Outcome measures included mean 6-TGN concentrations (+/-95% confidence interval [CI95%]) and their associations with TPMT genotype, 6-TG dose, and hematological, hepatic, pancreatic, and efficacy parameters during the 8 week period. Steady-state 6-TGN concentrations were reached after 4 weeks, indicating a half-life of approximately 5 days, and measured 856 (CI95% 715-997) pmol/8 x 10 RBCs. Large interpatient variability occurred at all time-points. No correlation was found between steady-state 6-TGN concentrations and drug dose per kilogram body weight. No significant differences in 6-TGN concentrations were found between patients with adverse events and patients without any event. Also, mean 6-TGN concentrations did not differ in patients with active disease versus patients in remission. In IBD patients on 6-TG treatment, large interindividual differences in metabolite concentrations occur. In our population, we could not demonstrate a clear relationship between 6-TGN concentrations on one hand and toxicity and efficacy on the other, as exist in AZA- and 6-MP-treated patients.

Adult↗

Endoscopic treatment of high-grade dysplasia and early stage cancer in Barrett's esophagus.

BACKGROUND: The aim of this study was to prospectively evaluate endoscopic resection (ER) combined with photodynamic therapy (PDT) for the treatment of selected patients with early neoplasia in Barrett's esophagus. METHODS: Patients with Barrett's esophagus and neoplastic lesions <2 cm in diameter and no sign of submucosal infiltration, positive lymph nodes, or distant metastasis underwent diagnostic ER (cap technique). Patients with a T1sm tumor in the resection specimen were referred for surgery; those with a T1m or a less invasive tumor underwent additional endoscopic therapy (ER, PDT, and/or argon plasma coagulation [APC]), or they were followed. PDT was performed with 5-aminolevulinic acid and a light dose of 100 J/cm 2 at lambda = 632 nm. RESULTS: Thirty-three patients underwent diagnostic ER. Endoscopic treatment was not performed in 5 patients, who underwent surgery (4 T1sm; 1, patient preference). Five patients were immediately entered into a follow-up protocol, and 23 received additional endoscopic treatment (13 additional ER, 19 PDT, 3 APC). Endoscopic treatment was successful in 26/28 patients; no severe complication was observed. During follow-up (median 19 months, range 13-24 months), 5/26 patients had a recurrence of high-grade dysplasia: all were successfully re-treated with ER. At the end of follow-up, 26/33 originally enrolled patients (79%) and 26/28 endoscopically treated patients (93%) were in local remission. CONCLUSIONS: Endoscopic therapy is safe and effective for selected patients with early stage neoplasia in Barrett's esophagus.

Aged↗

A comparative analysis by SAGE of gene expression profiles of Barrett's esophagus, normal squamous esophagus, and gastric cardia.

BACKGROUND & AIMS: The metaplastic process in which the normal squamous epithelium of the distal esophagus is replaced by columnar-lined epithelium, known as Barrett's esophagus (BE), is poorly understood. The aim of this study was to define, analyze, and compare transcription profiles of BE, normal cardia epithelium, and squamous epithelium to gain more insight into the process of metaplasia and to identify uniquely expressed genes in these epithelia. METHODS: Serial analysis of gene expression was applied for obtaining transcription libraries of biopsy specimens taken from a BE-affected patient with intestinal type of metaplasia and from normal squamous and gastric cardia epithelia. Validation of results by reverse-transcription polymerase chain reaction and immunoblotting was performed using tissues of 20 patients with BE. RESULTS: More than 120,000 tags were sequenced. Between BE and squamous 776, and between BE and gastric cardia 534 tags were significantly differentially expressed (P < .05, pairwise comparison). In contrast, squamous compared with gastric cardia epithelia showed significant differential expression of 1316 tags. The most up-regulated genes in BE compared with squamous epithelium were trefoil factors, annexin A10, and galectin-4. Each of the epithelia showed a unique cytokeratin expression profile. CONCLUSIONS: This study provides a comparison of the transcriptomes of BE, squamous epithelium, and gastric cardia epithelium. BE proves to be an incompletely differentiated type of epithelium that shows similarities to both normal squamous and gastric cardia epithelia. In addition, several uniquely expressed genes are identified. These results are a major advancement in understanding the process of metaplasia that leads to BE.

Adult↗

Dedicated pinhole SPECT of intestinal neutrophil recruitment in a mouse model of dextran sulfate sodium-induced colitis.

UNLABELLED: Evaluating the efficacy of therapy in experimental inflammatory bowel disease (IBD) requires information about inflammatory activity in bowel segments or leukocyte recruitment and about kinetics in the follow-up of treatment. This study evaluated a noninvasive scintigraphic technique able to assess neutrophil trafficking in a mouse model of dextran sulfate sodium (DSS)-induced colitis. METHODS: Groups of 4 BALB/c mice were assessed at baseline and after 1, 3, 5, and 8 d of treatment with DSS. Donor neutrophils were harvested by rinsing of the peritoneal cavity with phosphate-buffered saline 5 h after intraperitoneal injection of proteose peptone contained in phosphate-buffered saline and labeled with freshly prepared (99m)Tc-hexamethylpropylene amine oxime (HMPAO). Pinhole SPECT of the abdomen was performed 1 h after reinjection of 50 MBq of labeled neutrophils. In addition, the severity of inflammation was determined by histologic examination. The possibilities of the technique were illustrated by scintigraphic assessment of neutrophil trafficking with and without blocking of neutrophil migration by a CD97 monoclonal antibody in mice with DSS-induced colitis. RESULTS: Colonic uptake of (99m)Tc-HMPAO neutrophils was determined with dedicated animal pinhole SPECT in mice with DSS-induced colitis and correlated well with histologic findings (R = 0.81) and wet colon weight (R = 0.87) and moderately with clinical weight loss (R = 0.62). The neutrophil uptake ratio was reduced significantly (P < 0.01) by blocking of neutrophil migration capacity with the CD97 antibody. CONCLUSION: Animal pinhole SPECT can be used to study inflammatory activity and neutrophil recruitment in vivo in experimental colitis.

Animals↗

DNA array analysis of the effects of aspirin on colon cancer cells: involvement of Rac1.

Aspirin and other non-steroidal anti-inflammatory drugs show efficacy in the prevention of colon cancer. The mechanism by which they do this is unclear. We used a commercially available DNA microarray to study changes in gene expression in 1176 cancer related genes in the HT29 colon cancer cell line induced by aspirin. Overall we find more genes that are significantly induced than are repressed. The pattern of gene expression changes is different at high concentrations of aspirin (5 mM) than at lower levels (500 and 50 microM). Genes involved in DNA damage signaling, nucleotide metabolism and the stress response are induced, and cell cycle related genes repressed. The small GTPase Rac1 is highly induced and this was confirmed by immunoblotting. We show using immunohistochemistry that Rac1 is expressed in mature colonocytes at the intercrypt table in human and mouse colon tissue. These results support the previous findings that aspirin has different actions at high concentrations than at low concentrations and further show the use of DNA array technology in the investigation of drug mechanisms of action. Furthermore, they point towards a role for Rac1 in the action of aspirin in colon cancer.

Animals↗

Indian Hedgehog is an antagonist of Wnt signaling in colonic epithelial cell differentiation.

Wnt signaling defines the colonic epithelial progenitor cell phenotype, and mutations in the gene adenomatous polyposis coli (APC) that activate the Wnt pathway cause the familial adenomatous polyposis coli (FAP) syndrome and most sporadic colon cancers. The mechanisms that regulate the transition of epithelial precursor cells into their differentiated derivatives are poorly characterized. We report that Indian hedgehog (Ihh) is expressed by mature colonocytes and regulates their differentiation in vitro and in vivo. Hedgehog (Hh) signaling restricts the expression of Wnt targets to the base of the colonic crypt in vivo, and transfection of Ihh into colon cancer cells leads to a downregulation of both components of the nuclear TCF4-beta-catenin complex and abrogates endogenous Wnt signaling in vitro. In turn, expression of Ihh is downregulated in polyps of individuals with FAP and expression of doxycycline-inducible dominant negative TCF4 (dnTCF4) restores Ihh expression in APC mutant DLD-1 colon cancer cells. These data identify a new Wnt-Hh axis in colonic epithelial renewal.

Adenomatous Polyposis Coli↗

P38 mitogen activated protein kinase is involved in the downregulation of granulocyte CXC chemokine receptors 1 and 2 during human endotoxemia.

Chemokine receptors CXC receptor (CXCR) 1 and 2, and their ligands interleukin (IL)-8 and growth-related oncogene alpha (GRO alpha), are principal regulators of neutrophil activation and migration. To investigate the role of p38 mitogen activated protein kinase (MAPK) in the regulation of CXCR expression during an inflammatory response in vivo, 24 healthy volunteers received an intravenous injection with lipopolysaccharide (LPS) preceded (-3 hr) by a specific p38 MAPK inhibitor (BIRB 796 BS) at a high dose (600 mg) or a low dose (50 mg) or a placebo. The LPS-induced reduction of neutrophil CXCR 1 and 2 expression, as determined by fluorescence-activated cell sorter analysis, was inhibited in volunteers receiving the high dose of the p38 MAPK inhibitor. The kinase inhibitor also dose dependently diminished the LPS-induced rises in plasma IL-8 and GRO alpha levels. These results indicate a principal role for p38 MAPK in regulating factors essential for neutrophil activation and chemotaxis in vivo.

Chemokine CXCL1↗

Endoscopy in inflammatory bowel diseases.

A correct diagnosis, adequate assessment of disease activity, avoidance of surgery by endoscopic interventions, and effective cancer surveillance make endoscopy crucial in the management of inflammatory bowel diseases (IBDs). Impressive technical developments of several endoscopic techniques over the past few decades have allowed a detailed visual impression of the affected gut and enable tissue sampling and various therapeutic interventions. Here we propose guidelines for endoscopy in inflammatory bowel disease, and review all currently available endoscopic techniques relevant to the proper treatment of IBD patients.

Catheterization↗

The pathogenicity of cytomegalovirus in inflammatory bowel disease: a systematic review and evidence-based recommendations for future research.

During recent years, a clear association between complicated courses of ulcerative colitis and the presence of cytomegalovirus (CMV) has been established. The exact pathogenic role of CMV in these patients remains unclear despite a great number of published reports. Therefore, we undertook a systematic review to appraise critically all available evidence in the literature on the role of CMV during inflammatory bowel disease. We identified and analyzed more than 30 case reports and 9 case series. Based on these results, we propose a model for viral replication during inflammation and provide recommendations for future research.

Colitis, Ulcerative↗

In vivo evaluation of 111In-labeled T-lymphocyte homing in experimental colitis.

UNLABELLED: Blockade of lymphocyte recruitment to the intestinal mucosa is considered a useful therapy for inflammatory bowel disease (IBD) and anti-alpha4 antibodies have clinical benefit in patients with active Crohn's disease. The aim of this study was to evaluate a scintigraphic technique to assess lymphocyte homing to the colon in 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced experimental colitis (TNBS colitis) in vivo. METHODS: TNBS-sensitized and nonsensitized murine total lymphocytes or CD4+ lymphocytes were radiolabeled with 111In-oxinate. Cells were injected into control mice (n = 5) or mice with TNBS colitis (n = 5). Specific abdominal radioactive uptake was determined by SPECT using a dedicated pinhole system 48 h after cell transfer. Radioactive colon uptake was correlated with histology and colon weight as parameters of inflammation. RESULTS: The radioactive colon uptake was most evident in mice with TNBS colitis that received sensitized lymphocytes (uptake ratio [mean +/- SEM], 0.51 +/- 0.03 vs. 0.22 +/- 0.04; P = 0.004). The sensitized 111In-labeled lymphocytes exacerbated colitis compared with nonsensitized lymphocytes. The colon uptake correlated well with both colon weight and histologic score (R2 = 0.836 and 0.933, respectively). The use of purified 111In labeled CD4+ lymphocytes resulted in a similar scintigraphic pattern. Administration of an anti-alpha4 antibody decreased radioactivity colon uptake of the (111)In-labeled cells compared with the control antibody in mice with TNBS colitis (uptake ratio, 0.72 +/- 0.14 to 0.33 +/- 0.03; P = 0.012). CONCLUSION: Animal pinhole SPECT can be applied for temporal and spatial analysis of the lymphocyte homing process in experimental colitis. This technique makes possible the in vivo evaluation of therapeutic efficacy of new drugs that interfere with lymphocyte migration. Moreover, colon uptake of radioactivity can be used as a parameter of disease activity in experimental colitis.

Animals↗

Dichotomy between Lactobacillus rhamnosus and Klebsiella pneumoniae on dendritic cell phenotype and function.

The reaction of the intestinal immune system to intestinal bacteria shows striking differences between various bacterial strains. Whereas Klebsiella pneumoniae induces a fierce proinflammatory reaction, the probiotic strain Lactobacillus rhamnosus has clear anti-inflammatory effect in gastrointestinal disease and allergy. The molecular basis for this dichotomy is poorly understood but is likely to involve different modulation of antigen-presenting dendritic cells (DC) by L. rhamnosus and K. pneumoniae. Hence we evaluated phenotypic and functional characteristics of DC matured in the presence of L. rhamnosus and K. pneumoniae. Monocyte-derived immature DC were cultured in the presence of live bacteria to obtain mature DC. Both micro-organisms induced maturation of immature DC as shown by CD83 and CD86 expression, but receptors involved in activation of Th1 cells were expressed predominantly on DC exposed to K. pneumoniae. In contrast to K. pneumoniae, maturation with L. rhamnosus resulted in lower TNF-alpha, IL-6, and IL-8 production by immature DC and lower IL-12 and IL-18 production by mature DC. Moreover, L. rhamnosus led to the development of T cells without a typical Th phenotype whereas K. pneumoniae induced a Th1 immune response, dependent mainly on IL-12 production. Thus our results strongly support the concept that differential modulation of DC explains the differences in the immune response to various bacterial strains and indicates that K. pneumoniae induces Th1 immune responses via DC.

Antigens, CD↗

Activation of the canonical beta-catenin pathway by histamine.

Histamine signaling is a principal regulator in a variety of pathophysiological processes including inflammation, gastric acid secretion, neurotransmission, and tumor growth. We report that histamine stimulation causes transactivation of a T cell factor/beta-catenin-responsive construct in HeLa cells and in the SW-480 colon cell line, whereas histamine did not effect transactivation of a construct containing the mutated response construct FOP. On the protein level, histamine treatment increases phosphorylation of glycogen synthase kinase 3-beta in HeLa cells, murine macrophages, and DLD-1, HT-29, and SW-480 colon cell lines. Furthermore, histamine also decreases the phosphorylated beta-catenin content in HeLa cells and murine macrophages. Finally, pharmacological inhibitors of the histamine H1 receptor counteracted histamine-induced T cell factor/beta-catenin-responsive construct transactivation and the dephosphorylation of beta-catenin in HeLa cells and in macrophages. We conclude that the canonical beta-catenin pathway acts downstream of the histamine receptor H1 in a variety of cell types. The observation that inflammatory molecules, like histamine, activate the beta-catenin pathway may provide a molecular explanation for a possible link between inflammation and cancer.

Alkaline Phosphatase↗

Gene therapy in the treatment of intestinal inflammation.

BACKGROUND: Local expression of anti-inflammatory or immunoregulatory genes may offer an alternative treatment of gastrointestinal inflammation. DISCUSSION: We review the basic requirements for gene therapy, the possible routes of delivery, and the different strategies for specific targeting focusing on gastrointestinal inflammation.

Gastroenteritis↗