TNF and aneurysm: TNF-α is a potent proinflammatory cytokine that has been shown to be upregulated in patients with AA.209 A study of single nucleotide polymorphisms (SNPs) in healthy populations and AAA patients found that the TNF-α-238G/A gene was associated with an increased risk of AA development.210 In elastase-induced AA mice, the number of TNF-α-secreting macrophages was significantly increased.145 Animal experiments have demonstrated that TNF-α promotes the inflammatory response during aneurysm progression.