MAPK3 and aneurysm: Kim et al analogously described that AngII increases SMC ROS production via ERK1/2 stimulation concomitantly while ROS induce ERK1/2 phosphorylation, thereby intensifying each other.57 Finally, we cannot rule out that AngII participates in aneurysm formation through an alternative mechanism, for example direct stimulation of MMP activation.58, 59 It is intriguing that the protective clinical benefit of losartan noted in several MFS clinical trials may be secondary to blockade of AngII‐stimulated ROS production.60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70