P274 - Hydrocortisone and noradrenaline down-regulate the expression of the constitutively expressed colonic epithelial antibacterial peptides

s of the 4th Congress of ECCO the European Crohn’s and Colitis Organisation S119 P274 Hydrocortisone and noradrenaline down-regulate the expression of the constitutively expressed colonic epithelial antibacterial peptides A. Javaid*, J. Goodhand, D. Rampton. Barts and the London School of Medicine and Dentistry, London, United Kingdom Introduction: Psychological stress worsens inflammation in inflammatory bowel disease (IBD). In experimental animals, stress increases intestinal mucosal ingress of bacteria [1] and in the skin modulates the expression of antibacterial peptides (ABPs) [2]. Aims: To test the hypothesis that constitutively expressed ABPs are inhibited by stress and predispose to relapse in patients with quiescent IBD, we have assessed the effects of three putative neurohumoral stress mediators, hydrocortisone, noradrenaline and histamine on colonic epithelial expression of human beta defensin-1 (hBD1) and lysozyme in vitro. Methods: Confluent cells from the human colon cancerderived cell HT29 line were incubated with the putative stress mediators for 24 hrs. RNA was subsequently extracted, reversed transcribed and gene expression of lysozyme and hBD1 determined using real-time PCR. Gene expression was calculated by relative quantification against the housekeeping gene, GAPDH, and calibrating the samples to untreated controls. For each mediator, 5 samples were included in the analysis, and differences sought using the Mann Whitney U test. Results are expressed as fold reduction (FR) from the vehicle control-treated samples for each mediator. Results: Hydrocortisone dose-dependently down-regulated expression of both hBD1 and lysozyme. Fold-reductions for hBD1 compared with untreated controls were FR 4.42 (mean) ±0.01 [SEM] for 10 9M, and 32±7.9, p < 0.01 for 10 6M hydrocortisone; for lysozyme, the equivalent FRs were 1.19±0.53 for 10 9M and 9.1±2.2, p < 0.01 for 10 6M hydrocortisone. Noradrenaline (10 6M) also reduced hBD1 (FR 4.8±0.9, p < 0.01) and lysozyme expression (FR 6.5±2.0). Histamine (10 6M) had no effect on the expression of either gene. Conclusions: These results suggest that psychological stress, by releasing hydrocortisone and noradrenaline, may downregulate the expression of constitutive antibacterial peptides, potentially allowing bacterial ingress and precipitating inflammation in the lamina propria. The inhibitory effects on antibacterial peptide expression of hydrocortisone could underlie its tendency when used therapeutically in IBD and other settings to predispose to sepsis.