Identifying Plasma Proteins Linked to Neutrophil Activationin Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is characterized by progressive aortic wall expansion, leading to a high risk of rupture with an associated mortality rate exceeding 50%. Inflammation is strongly linked to medial matrix changes in AAA and includes positive correlations with C-reactive protein (CRP) and serum amyloid A (SAA). The neutrophil, therefore, may be a driver cell in AAA. The goal of this study was to identify plasma proteins that indicate neutrophil activation, an understudied component of the inflammatory response to AAA. Using a longitudinal study design, we analyzed plasma samples from patients with AAA (n=113) taken at time 0, 12, and 24 months after enrollment by mass spectrometry. We determined which proteins correlated with CRP, CRP slope over 2-year follow-up, and SAA, with the idea being that proteins consistent across all 3 evaluations had a higher potential to be true candidates. Proteins that positively correlated with CRP, CRP slope, and SAA included alpha-1-acid glycoprotein, beta-2-microglobulin, leucine-rich alpha-2-glycoprotein, and cluster of differentiation (CD)14. The first inhibits and the other 3 stimulate neutrophil activation. Focusing on the neutrophil contribution to AAA could lead to better screening, monitoring, and management strategies for AAA, ultimately improving patient outcomes. We acknowledge support from the NIH, the U.S. Department of Veterans Affairs Office of Research and Development, and the American Heart Association. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.