Copyright ©The Author(s) 2018.
World J Gastroenterol. Nov 14, 2018; 24(42): 4721-4727
Published online Nov 14, 2018. doi: 10.3748/wjg.v24.i42.4721
Table 1 Action of Aspirin on platelets and gastrointestinal mucosa and its unique features compared with other nonsteroidal anti-inflammatory drugs
Aspirin is a non-selective inhibitor of cyclooxygenase (COX), an enzyme involved in the synthesis of prostaglandins and thromboxanes (TXA) from arachidonic acid
Aspirin inhibits both COX-1 and COX-2 isoforms with a greater inhibition of COX-1 than COX-2 (approximately 100-fold) in low doses COX-1 isoform is expressed constitutively in most tissues: Gastrointestinal mucosa and kidneys and by generating prostaglandin E2 (PGE2) and prostacyclin (PGI2) and plays a critical role in maintaining tissue integrity at basal level COX-1-induced thromboxane A2 (TXA2) generation causes platelet aggregation and thrombi formation and is the basis for cardiovascular events
COX-2 isoform is constitutively expressed in some tissues (the brain, kidneys, intestine, and endothelial cells). In other tissues COX2 is induced in response to local irritants, proinflammatory cytokines and growth factors.
COX2 generated prostaglandins PGE2 and PGI2 play a critical role in gastric mucosal defense in response to injury and promote angiogenesis, ulcer healing, and (cancer growth)
Aspirin–has potent antithrombotic and cardioprotective properties: Irreversibly inactivates platelet COX-1 (vs only temporary inhibition by other nonselective NSAIDs)
↓ TXA2 synthesis, platelet aggregation, and thrombi formation which are all basis for cardiovascular events
↓ Cardiocerebrovascular events
In addition, aspirin may prevent and/or reduce cancer. A recent meta-analysis of 8 trials[38,39] showed that LDA reduces cancer incidence and mortality
Aspirin advantage - single daily dose, low cost, good safety profile