We appreciate Shen and colleagues for their insightful communication regarding the presence and localization of mesenchymal stromal cells (MSCs) in the human abdominal aortic aneurysm (AAA) wall, and for citing our work.1 As they note, identifying MSCs in the human vascular wall is challenging due to the lack of universally accepted markers. This issue is particularly evident in injured tissues like AAAs, where inflammation, oxidative stress, hypoxia, and other stress factors coexist in the atherosclerotic environment.2 Moreover, vascular wall cell plasticity and differentiation processes contribute to the loss of cellular hierarchy, such as with endothelial-to-mesenchymal transition. This process induces endothelial cells to acquire mesenchymal stem cell characteristics with pro-calcific potential,3 further complicating MSC identification.