Association of Aneurysm Tissue Neutrophil Mediator Levels with Intraluminal Thrombus Thickness in Patients with Abdominal Aortic Aneurysm

Abstract

An intraluminal thrombus (ILT), which accumulates large numbers of neutrophils, plays a key role in abdominal aortic aneurysm (AAA) pathogenesis. This study aimed to compare levels of selected neutrophil inflammatory mediators in thick and thin ILT, plus adjacent AAA walls, to determine whether levels depend on ILT thickness. Neutrophil mediator levels were analysed by enzyme-linked immunosorbent assays in thick and thin segments of ILT, plus adjacent aneurysm wall sections, taken from one aneurysm sac each from 36 AAA patients. In aneurysmal walls covered by thick ILT, neutrophil elastase and TNF-a levels were significantly higher, as were concentrations of IL-6, in thick ILT compared to thin layers. Positive correlations of NGAL, MPO, and neutrophil elastase were observed between thick ILT and the adjacent wall and thin ILT and the adjacent wall, suggesting that these mediators probably infiltrate thick AAA compartments as well as thin. These observations might support the idea that neutrophil mediators and inflammatory cytokines differentially accumulate in AAA tissues according to ILT thickness. The increased levels of neutrophil mediators within thicker AAA segments might suggest the existence of an intensified proinflammatory state that in turn presumably might preferentially weaken the AAA wall at that region.

Single-cell transcriptome analysis reveals the cellular atlas of human intracranial aneurysm and highlights inflammation features associated with aneurysm rupture

“…Granulocyte, namely neutrophil (G0S2, PULA, FCGR3B) in this condition 35,36 , was the most abundant immune cell in IA. The high proportion of neutrophils (31.1%) was found even in the unruptured sample.…”

Calprotectin as a new inflammatory marker of abdominal aortic aneurysm: A pilot study

“…However, the effect of MPO in larger AAAs appear to be controversial. Whereas Siennicka et al 22 observed a decrease in plasma MPO levels in patients with AAA, Zagrapan et al 23 reported an increase in this biomarker. These discrepancies between groups highlight the importance of further research into neutrophil biomarkers in AAA, as different AAA stages, inclusion criteria, and patient characteristics like comorbidities or medication may affect the levels of some of these molecules.…”

Antiplatelet or Anticoagulant Therapy for Abdominal Aortic Aneurysms: Growth and Clinical Outcomes

“…Therefore, the thrombus causes a lack of wound healing in the aortic media, leading to increased aortic weakness and dilatation. 7 Whether antiplatelet and anticoagulant therapy affects aneurysmal dilatation and rupture is controversial. Currently, low-dose aspirin is recommended for patients with AAA, but the evidence is controversial.…”

“…It has been demonstrated that ILT formation and growth are active and dynamic processes. 7 Evidence has shown that AAA rupture is a result of mechanical stress on the arterial wall. Some studies suggested that an increase in thrombus diameter might decrease mechanical stress as a mechanical cushion; therefore, preventing the aortic diameter from increasing.…”