Letter by Pinheiro et al regarding article, "unexpected effect of proton pump inhibitors: elevation of the cardiovascular risk factor asymmetric dimethylarginine".

Ghebremariam et al1 showed compelling evidence that proton pump inhibitors (PPIs) reduce the endogenous formation of nitric oxide (NO) and impair endothelium-dependent vasodilation. The deleterious effects of PPIs are explained by inhibition of the enzyme dimethylarginine dimethylaminohydrolase, which degrades asymmetrical diemethylarginine, and, therefore, the use of PPIs increases the concentrations of this endogenous NO synthase inhibitor.1 Although their findings are of utmost importance because they may explain how PPIs contribute to cardiovascular events, we would like to add further evidence implicating another …