After conditionally knocking out Tff1 in Tregs, the protective effect of aorta Tregs was attenuated, as indicated by increased aneurysm diameter (Figure 6e), extensive degradation of elastin in the media of the vessel wall (Figure 6f) and increased apoptosis of SMCs (Figure 6g), and there was no difference in the sham operated group (Figure 6e–g). This evidence concerns the gene TFF1 and aneurysm.