OLA1 and atherosclerosis: The second limitation is that, although our study revealed that OLA1 was required to promote proliferation and migration of human aortic ECs and SMCs and vascular tube formation by human aortic ECs in a cell culture system, we cannot clarify whether loss of OLA1 in vascular ECs or SMCs would cause development of atherosclerosis or whether overexpression of OLA1 in vascular ECs or SMCs would cause development of atherosclerosis.