Ornithine Decarboxylase (gene name ODC1) is the rate limiting enzymes of the polyamine biosynthesis pathway and catalyzes ornithine to putrescine. The activity level for the enzyme varies in response to growth-promoting stimuli and exhibits a high turnover rate in comparison to other mammalian proteins. Interestingly, this enzyme (as well as its inhibitor, Ornithine decarboxylase antizyme, gene name OAZ1) is also differentially expressed at higher levels in platelets from individuals with sickle cell disease than in in those without sickle cell disease (PMCID: PMC2225987). Platelets are in a basally activated state in patients with sickle cell disease and may contribute to at least some of the long-term vascular complications seen in patients with sickle cell disease. In patients with CAD, variants in OAZ1 have shown to be associated with increased risk of 6-month in-stent restenosis, increase in carotid intima-media thickness over the a 4-year period, and an increased risk of CAD (PMID: 17761941).
Aspirin is widely used for its anti-platelet effects and is also shown to be beneficial in reducing the recurrence of colon adenomatous polyps. A recent study has found that variants located downstream of the 3’ end of ODC1 gene may influence the risk of colorectal adenoma and impact the efficacy of aspirin. (PMID: 21930798)Whether there is a similar relationship between the antiplatelet effect of aspirin and ODC1 gene variants is unknown. Although one may be tempted to postulate that such a relationship exists based on the above noted studies, there are other potential mechanisms that may play a role. For example, ornithine decarboxylase has been shown to affect proliferation of vascular smooth muscle cells (PMID: 21894530) and the function of endothelial cells (PMID: 20594968); both cell types important in the process of atherosclerosis.
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