CCL2 and triple-A syndrome: Pro-inflammatory factors such as IL1-β, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and C-C motif chemokine ligand (CCL)-2 can accelerate the progression of AAA, while anti-inflammatory factors such as Arg1, IL10, and TGF-β can promote repair and prevent AAA rupture to a certain extent; therefore, the balance of these inflammatory factors regulated by the gut microbiome affects AAA pathological progression (12).