NSAID-Phosphatidylcholine Association: Insight in GI Ulcer Pathogenesis/Therapy

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DESCRIPTION (provided by applicant): This application addresses broad Challenge Area (15) Translational Science and specific Challenge Topic, 15-DK-103: "Translate discovery of new molecules/pathways in pathogenesis of NIDDK diseases in potential therapies." We have assembled a team of experts to characterize the mechanism by which nonsteroidal anti-inflammatory drugs (NSAIDs) chemically associate with and destabilize phosphatidylcholine(PC) that plays an important role in the surface barrier property of the GI mucosa . This mechanism is independent of the ability of the drugs' to inhibit cyclooxygenase (COX) and is exacerbated by bile acids, that are present in high concentration to the lumen of the small intestine, by forming toxic mixed micelles due to their common amphipathic properties. The latter is consistent with recent capsule endoscopy evidence suggesting that NSAID-induced injury to the lower gut is much more prevalent than was once thought, affecting as much as 40% of chronic NSAID users. To elucidate the chemical associations between NSAIDs, PC and bile acids we propose to use: molecular dynamic (MD) simulation; surface plasmon resonance (SPR); and nuclear magnetic resonance (NMR) spectroscopy. To study the nanoparticles formed by these associations we propose a series of experiments with synthetic liposomal/micellar systems using: dynamic light scattering for size determination, and fluorescent probes such as, fluorescent resonance energy transfer (FRET) and dye exclusion analysis to assess the effects of NSAID bile acid interactions on membrane fluidity, microdomain formation and permeability. Studies on gastric and intestinal cell lines are proposed to evaluate the effects of our treatment on biological membranes as assessed by cellular - imaging (using fluorescent probes) - permeability and replication. These studies will then be translated to rodent models of NSAID-induced GI ulceration bleeding/ulceration and therapeutics, that are readily available in the PI's lab. Lastly, Challenge grant support will be used to partially defray the expense of performing the required formulation optimization, manufacturing and stability analyses of our first PC-NSAID under development (Ibuprofen-PC) by a university-based start-up company, PLx Pharma founded by the PI, to meet FDA requirements to obtain an New Drug Application, so that this novel class of GI-safer NSAIDs can be made available to the public. PUBLIC HEALTH RELEVANCE: Due to their remarkable efficacy to inhibit pain, inflammation and fever and their preventative efficacy for diseases such as cancer, stroke, thrombosis and Alzheimer's disease, it has been estimated that NSAIDs are consumed by ~70 million Americans on a chronic basis. The major health concern with this trend, is that the consumption of NSAIDs is well known to be associated with side-effects, with GI ulceration and bleeding being most common, accounting for 400,000 people being hospitalized at an estimated cost of $ 124.8 billion/yr and 16,000-20,000 deaths annually. With the withdrawal of selective COX-2 inhibitors, such as Vioxx, there is a great "unmet need" for novel strategies to understand and prevent NSAID-induced GI side-effects. This Translational Science Challenge grant is focused on understanding how NSAIDs chemically associate with and destabilize phosphatidylcholine(PC) that plays an important role in the surface barrier property of the GI mucosa. Furthermore, by pre-associating soy PC with NSAIDs we have developed a novel family GI-safer, therapeutically effective PC-NSAIDs that can be made available to the public using an accelerated FDA regulatory pathway.