Long-term objective: to show that CAM can benefit patients with inflammatory bowel disease (IBD)-two chronic, life-long relapsing disorders, Crohn's Disease & Ulcerative Colitis. Immediate objective: to see if herbal mixtures reputed to be anti-inflammatory and used by IBD patients are protective in an in vitro model of IBD-monolayers of intestinal cells. Strategy: we will use this model to test herbal effects and mechanisms because of the model's established relevance to oxidative injury, loss of barrier integrity and IBD. Background: using this model we showed that oxidants disrupt the barrier by oxidizing and disrupting the cytoskeleton via NF-kappaB activation and iNOS upregulation. Protection is afforded by agents that counteract this cascade. Our recent pilot data suggest that a mixture of anti-inflammatory herbs that is used by IBD patients, Varcho Veda, protects monolayers against oxidant-induced damage, possibly by counteracting this cascade. Hypotheses: HI: Varcho Veda herbs protect monolayers against oxidant-induced damage. H2: Herbs protect by counteracting the oxidant-induced cascade.
Aim #1 : To see if herbs protect barrier integrity against oxidant-induced injury and, if so, whether the protection requires protection of cytoskeletal integrity.
Aim #2 : To see if protection requires inhibition of NF-kappaB activation and iNOS upregulation. In both aims, we will expose monolayers to H202 + herbs, individually or as a mixture identical to that taken by CAM-using IBD patients. Outcomes include barrier & cytoskeletal integrity, protein oxidation, iNOS, NF-kappaB activation, and I-kappaB degradation. In selected experiments, monolayers made of transfected cells will be used to further assess the roles of iNOS and NF-kappaB. Significance: Showing that our herbs protect, and do so via anti-oxidant mechanisms will (i) provide a rationale for a clinical trial for these herbs in IBD patients, (ii) suggest that herbs may work by preventing inflammatory cascades that arise from dysregulation of endogenous signaling mechanisms, (iii) suggest the potential efficacy of anti-oxidant and CAM approaches to IBD. Our monolayer model might provide a rapid, in vitro screen for identifying promising candidate herbs or anti-oxidants that should go on to evaluation in vivo in translational studies of oxidation, cytoskeletal & barrier disruption and inflammation (we recently showed that similar oxidative changes and cytoskeletal damage occur in intestinal mucosa of IBD patients).
| Banan, A; Keshavarzian, A; Zhang, L et al. (2007) NF-kappaB activation as a key mechanism in ethanol-induced disruption of the F-actin cytoskeleton and monolayer barrier integrity in intestinal epithelium. Alcohol 41:447-60 |
