title: Surface phospholipids in gastric injury and protection when a selective cyclooxygenase-2 inhibitor (Coxib) is used in combination with aspirin.
abstract: OBJECTIVE
  Clinical studies demonstrate that aspirin consumption reverses the gastrointestinal (GI) benefits of coxibs, by an undefined mechanism.
  
  
  METHODS
  Rodent models were employed to investigate the effects of combinations of celecoxib and aspirin on gastric ulcerogenesis, bleeding, surface hydrophobicity (by contact angle analysis) and ulcer healing. We also evaluated the effects of phosphatidylcholine (PC)-associated aspirin in these rodent models and confirmed its cyclooxygenase (COX)-inhibitory activity by measuring mucosal prostaglandin E(2) (PGE(2)) concentration. We present evidence that aspirin's ability to induce gastric injury and bleeding in rats, was exacerbated in the presence of a coxib and was dependent on its ability to reduce gastric surface hydrophobicity. In contrast, co-administration of phosphatidylcholine (PC)-associated aspirin and celecoxib induced little or no gastric injury/bleeding and maintained the stomach's hydrophobic properties. Interestingly, aspirin and aspirin/PC equally inhibited gastric mucosal PGE(2) concentration. Aspirin in combination with a coxib retarded the healing of experimentally induced gastric ulcers, whereas healing rates of rats treated with celecoxib in combination with aspirin/PC were comparable to controls.
  
  
  CONCLUSIONS
  Aspirin's gastric toxicity in combination with a coxib can be dissociated from its ability to inhibit COX-1 and appears to be dependent, in part, on its ability to attenuate the stomach's surface hydrophobic barrier. This adverse drug interaction between aspirin and coxibs, which impacts the treatment of osteoarthritic and cardiac patients requiring cardiovascular prophylaxis, can be circumvented by the administration of phosphatidylcholine (PC)-associated aspirin, to maintain the stomach's hydrophobic properties.
authors.affiliation: The Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, TX 77030, USA. lenard.m.lichtenberger@uth.tmc.edu
authors.forename: L M
authors.initials: LM
authors.lastname: Lichtenberger
authors.forename: J J
authors.initials: JJ
authors.lastname: Romero
authors.forename: E J
authors.initials: EJ
authors.lastname: Dial
mesh_terms: D000818:Animals; D001241:Aspirin / Q000008:administration & dosage* / Q000009:adverse effects; D000068579:Celecoxib; D016861:Cyclooxygenase Inhibitors / Q000008:administration & dosage*; D015232:Dinoprostone / Q000378:metabolism; D004347:Drug Interactions; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D057927:Hydrophobic and Hydrophilic Interactions; D008297:Male; D010713:Phosphatidylcholines / Q000008:administration & dosage*; D011720:Pyrazoles / Q000008:administration & dosage* / Q000009:adverse effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013276:Stomach Ulcer / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D013449:Sulfonamides / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D016861:Cyclooxygenase Inhibitors; D010713:Phosphatidylcholines; D011720:Pyrazoles; D013449:Sulfonamides; D000068579:Celecoxib; D015232:Dinoprostone; D001241:Aspirin