Fig. 2

Macrophage polarization in AA and its functions. M1 and M2 polarization of macrophages derived from circulating monocytes were found to be closely related with the development and prognosis of AA. The chronic inflammatory microenvironments at the site of AA, such as the expression of IFNs, LPS, TNF and M-CSF, induce M1 macrophages, which function as pro-inflammatory macrophages; in response to inflammation, they can cause tissue damage related to the development of AA. On the other hand, M2 macrophages induced by IL-10 and TGFβ can function as anti-inflammatory macrophages, which play a key role in tissue remodeling. Some molecules or factors have been reported to induce the transformation of M1 macrophages into M2 macrophages, such as Everolimus, EPA & DHA, D-series resolvins, Tregs and MSCs. AngII angiotensin II, AA aortic aneurysm, ApoE apolipoprotein E, MMP matrix metalloproteinase, Tregs regulatory T cells, BM-MSC bone marrow derived mesenchymal stem cells, IL-1β interleukin-1β, EPA eicosapntemacnioc acid, DHA docosahexaenoic acid, TGFβ transforming growth facto, M-CSF macrophage colony-stimulating factor