Defensins are endogenous antimicrobial peptides that protect the intestinal mucosa against bacterial invasion. It has been suggested that deficient defensin expression may underlie the chronic inflammation of Crohn disease (CD). The DNA copy number of the beta-defensin gene cluster on chromosome 8p23.1 is highly polymorphic within the healthy population, which suggests that the defective beta-defensin induction in colonic CD could be due to low beta-defensin-gene copy number. Here, we tested this hypothesis, using genomewide DNA copy number profiling by array-based comparative genomic hybridization and quantitative polymerase-chain-reaction analysis of the human beta-defensin 2 (HBD-2) gene. We showed that healthy individuals, as well as patients with ulcerative colitis, have a median of 4 (range 2-10) HBD-2 gene copies per genome. In a surgical cohort with ileal or colonic CD and in a second large cohort with inflammatory bowel diseases, those with ileal resections/disease exhibited a normal median HBD-2 copy number of 4, whereas those with colonic CD had a median of only 3 copies per genome (P=.008 for the surgical cohort; P=.032 for the second cohort). Overall, the copy number distribution in colonic CD was shifted to lower numbers compared with controls (P=.002 for both the surgical cohort and the cohort with inflammatory bowel diseases). Individuals with < or = 3 copies have a significantly higher risk of developing colonic CD than did individuals with > or = 4 copies (odds ratio 3.06; 95% confidence interval 1.46-6.45). An HBD-2 gene copy number of < 4 was associated with diminished mucosal HBD-2 mRNA expression (P=.033). In conclusion, a lower HBD-2 gene copy number in the beta-defensin locus predisposes to colonic CD, most likely through diminished beta-defensin expression.

Tumor necrosis factor-alpha (TNFalpha) is a key proinflammatory cytokine involved in chronic inflammatory diseases. Infliximab, a chimeric (human-murine) monoclonal IgG1 anti-TNFalpha antibody, is used in the treatment of Crohn's disease (including fistulising disease) and rheumatoid arthritis (in combination with methotrexate) if standard treatments have failed. The indications for infliximab have recently been expanded to include ankylosing spondylitis, psoriatic arthritis, psoriasis and ulcerative colitis. The biological agent infliximab is given by multiple intravenous infusions in a dosage of 3-5 mg/kg (initially at weeks 0, 2 and 6; subsequently in intervals of 4-8 weeks). In controlled trials, clinical response rates of 20-40% have been achieved with such regimens in Crohn's disease and rheumatoid arthritis. However, the therapeutic benefits must be balanced against the risks of a variety of severe adverse events (e.g. severe infections including tuberculosis, hepatotoxicity, infusion reactions, serum sickness-like disease and lymphoma). Following single and multiple infusions of infliximab, no relevant differences in median concentration-time profiles have been observed between patients with Crohn's disease, patients with rheumatoid arthritis and patients with psoriasis. The apparent volume of distribution of the high-molecular-weight infliximab (149.1 kDa) is low (3-6L) and represents the intravascular space. The long persistence in this compartment (elimination half-life 7-12 days, mean residence time 12-17 days) is due to the very low systemic clearance of about 11-15 mL/hour (0.18-0.25 mL/minute). Elimination of infliximab is most probably accomplished through degradation by unspecific proteases. During multiple infusions (every 4-8 weeks), no accumulation was observed, and serum concentrations and the area under the plasma concentration-time curve of infliximab increased in proportion to the infused dose, indicating linear pharmacokinetics. Co-medication with methotrexate delayed the decline in the serum concentrations of infliximab. When relating serum concentrations to the clinical response in patients with rheumatoid arthritis and patients with Crohn's disease, it can be assumed that trough concentrations above 1 microg/mL could be used as a kind of therapeutic target. In the future, identification of biomarkers for (non-)response and risk factors for adverse drug reactions would be very helpful. Furthermore, combined biological, pharmacokinetic, pharmacogenomic and clinical studies have not yet been performed and are needed to optimise the therapeutic potential of infliximab, which is currently established as a rescue treatment in refractory patients.

Reduced expression of Paneth cell antimicrobial α-defensins, human defensin (HD)-5 and -6, characterizes Crohn's disease (CD) of the ileum. TCF-4 (also named TCF7L2), a Wnt signalling pathway transcription factor, orchestrates Paneth cell differentiation, directly regulates the expression of HD-5 and -6, and was previously associated with the decrease of these antimicrobial peptides in a subset of ileal CD. To investigate a potential genetic association of TCF-4 with ileal CD, we sequenced 2.1 kb of the 5′ flanking region of TCF-4 in a small group of ileal CD patients and controls (n = 10 each). We identified eight single nucleotide polymorphisms (SNPs), of which three (rs3814570, rs10885394, rs10885395) were in linkage disequilibrium and found more frequently in patients; one (rs3814570) was thereby located in a predicted regulatory region. We carried out high-throughput analysis of this SNP in three cohorts of inflammatory bowel disease (IBD) patients and controls. Overall 1399 healthy individuals, 785 ulcerative colitis (UC) patients, 225 CD patients with colonic disease only and 784 CD patients with ileal involvement were used to determine frequency distributions. We found an association of rs3814570 with ileal CD but neither with colonic CD or UC, in a combined analysis (allele positivity: OR 1.27, 95% CI 1.07 to 1.52, p = 0.00737), which was the strongest in ileal CD patients with stricturing behaviour (allele frequency: OR 1.32, 95% CI 1.08 to1.62, p = 0.00686) or an additional involvement of the upper GIT (allele frequency: OR 1.38, 95% CI 1.03 to1.84, p = 0.02882). The newly identified genetic association of TCF-4 with ileal CD provides evidence that the decrease in Paneth cell α-defensins is a primary factor in disease pathogenesis.

Objective The aim of the study was to compare azathioprine versus mesalazine tablets for the prevention of clinical recurrence in patients with postoperative Crohn's disease (CD) with moderate or severe endoscopic recurrence. Methods This was a 1 year, double-blind, doubledummy, randomised study which took place in 21 gastroenterology centres in Austria, the Czech Republic, Germany and Israel. The study participants were 78 adults with CD who had undergone resection with ileocolonic anastomosis in the preceding 6e24 months without subsequent clinical recurrence and with a Crohn's disease activity index (CDAI) score <200, but with moderate or severe endoscopic recurrence. The study drugs were azathioprine 2.0e2.5 mg/kg/day or mesalazine 4 g/day over 1 year. The primary end point was therapeutic failure during 1 year, defined as a CDAI score $200 and an increase of $60 points from baseline, or study drug discontinuation due to lack of efficacy or intolerable adverse drug reaction. Results Treatment failure occurred in 22.0% (9/41) of azathioprine-treated patients and 10.8% (4/37) of mesalazine-treated patients, a difference of 11.1% (95% CI À5.0% to 27.3%, p¼0.19). Clinical recurrence was significantly less frequent with azathioprine versus mesalazine (0/41 (0%) vs 4/37 (10.8%), p¼0.031), whereas study drug discontinuation due to adverse drug reactions only occurred in azathioprine-treated patients (9/41 (22.0%) vs 0%, p¼0.002). The proportion of patients showing $1 point reduction in Rutgeerts score between baseline and month 12 was 63.3% (19/30) and 34.4% (11/32) in the azathioprine and mesalazine groups, respectively (p¼0.023). Conclusions In this population of patients with postoperative CD at high risk of clinical recurrence, superiority for azathioprine versus mesalazine could not be demonstrated for therapeutic failure. Clinical trial registration number NCT00946946.

Defined angiographically, no-reflow (NR) manifests as an acute reduction in coronary flow in the absence of epicardial vessel obstruction. One candidate protein to cause coronary NR is tissue factor (TF), which is abundant in atherosclerotic plaque and a cofactor for activated plasma coagulation factor VII. Scrapings from atherosclerotic carotid arteries contained TF activity (corresponding to 33.03 ؎ 13.00 pg/cm 2 luminal plaque surface). Active TF was sedimented, indicating that TF was associated with membranes. Coronary blood was drawn from 6 patients undergoing coronary interventions with the distal protection device PercuSurge GuardWire (Traatek, Miami, FL). Fine particulate material that was recovered from coronary blood showed TF activity (corresponding to 91.1 ؎ 62.16 pg/mL authentic TF). To examine the role of TF in acute coronary NR, blood was drawn via a catheter from coronary vessels in 13 patients during NR and after restoration of flow. Mean TF antigen levels were elevated during NR (194.3 ؎ 142.8 pg/mL) as compared with levels after flow restoration (73.27 ؎ 31.90 pg/mL; P ‫؍‬ .02). To dissect the effects of particulate material and purified TF on flow, selective intracoronary injection of atherosclerotic material or purified relipidated TF was performed in a porcine model. TF induced NR in the model, thus strengthening the concept that TF is causal, not just a bystander to atherosclerotic plaque material. The data suggest that active TF is released from dissected coronary atherosclerotic plaque and is one of the factors causing the NR phenomenon. Thus, blood-borne TF in the coronary circulation is a major determinant of flow. (Blood. 2002;99:2794-2800)

Almost one-half of the (-)-epicatechin is apparently absorbed in the jejunum but with substantial interindividual differences in the extent of absorption. The data suggest that the nature and substitution position of (-)-epicatechin conjugation are major determinants of the metabolic fate in the body, influencing whether the compound is effluxed into the lumen or absorbed into the blood and subsequently excreted.

The data elucidate the pathways of metabolism of dietary hesperidin in vivo and will facilitate better design of mechanistic studies both in vivo and in vitro.

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