M. E. Diebel1, D. M. Liberati1, L. N. Diebel1 1Wayne State University,Michael And Marian Ilitch Department Of Surgery,Detroit, MI, USA
Introduction: Intestinal barrier injury occurs following major trauma and leads to an intestinal inflammatory response and subsequent remote organ dysfunction. This response may be modulated by either vagal nerve stimulation or pharmacologic stimulation of the alpha7-cholinergic receptor (nAChR) anti-inflammatory pathway. The downstream mediators in this pathway are relatively unknown. Gut injury is also associated with the release of endogenous damage associated molecular patterns (DAMPs) which may modulate shock induced organ dysfunction. The impact of stimulation of the intestinal cholinergic anti-inflammatory pathway on DAMPs release and resultant tissue injury was studied in vitro.
Methods: Intestinal epithelial cell (IEC-6) monolayers were subjected to hypoxia-reoxygenation (H/R) challenge. Cell subsets were treated after hypoxic challenge with nicotine or AR-R17779, a specific nAChR agonist. Nuclear factor kappa light-chain-enhancer of activated B cell (NFkB) activation was determined by ELISA and IEC monolayer integrity was indexed by permeability to an FITC-dextran probe (4,000 mw; FD-4). DAMPs production was indexed by high mobility group box 1 (HMGB-1) (western blot) and mitochondrial DNA (coxIII using RT-PCR) release. Human pulmonary microvascular endothelial cells (HMVEC) were then co cultured with IEC culture supernatants and monolayer permeability and ICAM-1 expression determined.
Results: mean ± S.D., N = 4 for each group
Conclusion: Pharmacologic stimulation of the nAChR pathway protected against H/R induced intestinal barrier derangement, NFkB activation and DAMPs release. Decreased IEC mediated DAMPs release was associated with protection against lung microvascular injury and ICAM-1 expression in this in vitro study. Modulation of this pathway may be helpful in the clinical setting.
