Abdominal Aortic Aneurysm: Roles of Inflammatory Cells

Abstract

Abdominal aortic aneurysms (AAAs) are local dilations of infrarenal segment of aortas. Molecular mechanisms underlying the pathogenesis of AAA remain not fully clear. However, inflammation has been considered as a central player in the development of AAA. In the past few decades, studies demonstrated a host of inflammatory cells, including T cells, macrophages, dendritic cells, neutrophils, B cells, and mast cells, etc. infiltrating into aortic walls, which implicated their crucial roles. In addition to direct cell contacts and cytokine or protease secretions, special structures like inflammasomes and neutrophil extracellular traps have been investigated to explore their functions in aneurysm formation. The above-mentioned inflammatory cells and associated structures may initiate and promote AAA expansion. Understanding their impacts and interaction networks formation is meaningful to develop new strategies of screening and pharmacological interventions for AAA. In this review, we aim to discuss the roles and mechanisms of these inflammatory cells in AAA pathogenesis.

Expression Pattern and Clinical Value of Key m6A RNA Modification Regulators in Abdominal Aortic Aneurysm

“…Studies have demonstrated that a host of immune cells can infiltrate into aortic walls of AAA, in which the roles of T lymphocytes and macrophages are predominantly studied. 3 In AAA tissues, correlation analysis between AAA-related m6A regulator expression and infiltrating immune cell score suggested that METTL14 or HNRNPC downregulation and RBM15B upregulation might inhibit the infiltration of Tcm, macrophages and mast cells, and promote several immune cell aggregation, such as Tgd and NK CD56bright cells. This indicated the important and connecting role of abnormal METTL14, RBM15B and HNRNPC expression in epigenetic modification and immune infiltration implicated in AAA pathogenesis.…”

“… 2 Immune inflammatory cells have been found to be in the central position of the whole process of AAA formation. 3 Recent researchers suggest that body metabolism is closely related to the initiation and development of AAA, while autophagy is an essential process mediating proper vascular function. 4 , 5 However, the complete mechanisms underlying AAA have not yet been elucidated.…”

STAT1 gain-of-function heterozygous cell models reveal diverse interferon-signature gene transcriptional responses

“…This can perhaps be related to our finding in the T385M mutant of enhanced transcriptional responses to IFNα across all genes measured, which is not observed in P329L. Indeed, increased type I IFN activity has been implicated in the pathogenesis of human aortic aneurysms 70 , 71 . However, the connection between specific phenotypic features and transcriptional patters emerging from this work remains early and speculative, and requires further work.…”

Heterogeneity of Ex Vivo and In Vivo Properties along the Length of the Abdominal Aortic Aneurysm

“…Higher inflammatory cell activity (CD4+, CD8+) in the adventitia was found in samples collected from regions in position 4 compared to position 2 and 3. The localized increase in helper T-cells (CD4+) and cytotoxic T-cells (CD8+) together in this region suggests the presence of CD4+ T-cell phenotype Th1, which has been implicated in ECM degradation [42]. CD4+ T-cells were also reported to release cytokines that stimulate angiogenesis and fibroblastic collagen accumulation in the adventitia.…”