PTGS1 and Alzheimer disease: The fact that NSAIDS inhibit cyclooxygenases (COX-1 and COX-2), the enzymes that convert arachidonic acid (AA) to prostaglandin H2 (PGH2), the precursor to all prostanoids and thromboxanes (Figure 1), strongly indicates that one or more of these eicosanoids is involved in AD onset.