Related Experiment Video
Updated: Jun 25, 2026
Measurement of Pulse Propagation Velocity, Distensibility and Strain in an Abdominal Aortic Aneurysm Mouse Model
Published on: February 23, 2020
Quantification of plasminogen activator inhibitor type 1 in the aortic wall
V Kríková1, M Korabecná, J Kocová
1Department of Histology and Embryology, Charles University, Pilsen, Czech Republic. vera.krizkova@lfp.cuni.cz
Insights
Plasminogen activator inhibitor type 1 (PAI-1) expression decreases in abdominal aortic aneurysms (AAA) with disease progression. PAI-1 redistribution in cells correlates with AAA clinical classification.
Area of Science:
- Vascular Biology
- Biochemistry
- Histopathology
Background:
- Plasminogen activator inhibitor type 1 (PAI-1) is crucial for regulating the fibrinolytic system and smooth muscle cell (SMC) migration.
- Understanding PAI-1 expression in abdominal aortic aneurysms (AAA) is vital for comprehending disease pathogenesis.
- Abnormalities in fibrinolysis are implicated in the development and progression of AAA.
Purpose of the Study:
- To identify PAI-1 expressing cells in AAA walls.
- To quantify PAI-1 expression levels in different stages of AAA.
- To correlate PAI-1 expression with histological and clinical findings in AAA patients.
Main Methods:
- Histological and immunohistochemical analysis of aortic wall samples from nine AAA patients (asymptomatic, symptomatic, ruptured) and one control.
- In situ hybridization was used for PAI-1 detection.
- Quantification of PAI-1 area fraction and cell expression (endothelium, SMC, foam cells) using Ellipse software and analysis by two independent observers.
Main Results:
- PAI-1 area fraction decreased from 28.6% in controls to 18.1% in asymptomatic AAA, 10.9% in symptomatic AAA, and 11.0% in ruptured AAA.
- Smooth muscle cells (SMC) were the primary cells expressing PAI-1, and their abundance decreased as AAA progressed.
- In ruptured AAA, PAI-1 was detected in the necrotic centers of atheromatous plaques.
Conclusions:
- Abdominal aortic aneurysms (AAA) development involves gradual changes in fibrinolysis regulation, evidenced by PAI-1 cell redistribution.
- The quantified area fraction of PAI-1 positive components shows a correlation with the clinical classification of AAA.
- PAI-1 expression patterns offer insights into AAA pathogenesis and progression.
Aim:
Plasminogen activator inhibitor type 1 (PAI-1) plays a key role in regulation of fibrinolytic system, cell-associated proteolysis and migration of smooth muscle cells (SMC). This study is focused on the types of PAI-1 expressing cells, quantification of PAI-1 expression in the walls of aneurysmatic abdominal aortas (AAA) and correlation between histological and clinical findings.
Methods:
A group of nine patients who underwent surgery for AAA: asymptomatic (aAAA), symptomatic (sAAA) and ruptured (rAAA) and one control specimen (CA) were included in the study. Samples underwent histological processing and immunohistochemistry in comparison with in situ hybridisation. In order to assess the PAI-1 area fraction in histological sections through the aortic wall the Line System module of Ellipse software was used. PAI-1 expressing cells were measured in CA and AAA: endothelium, SMC, and foam cells. Photomicrographs with a total area of 0.7 mm(2) for each specimen were analysed by two independent observers. Mean values of PAI-1 positive components per section area were calculated as average values.
Results:
The results of both observers are as follows: 28.6% in CA; 18.1% in aAAA; 10.9% in sAAA; 11.0% in rAAA. During the progression of AAA, the SMC (PAI-1 expression was found mainly in them) became less abundant in agreement with the values of PAI-1 area fraction. In rAAA immunohistochemistry detected PAI-1 in necrotic centres of atheromathous plaques.
Conclusions:
AAA may be evaluated as the result of gradual changes in regulation of fibrinolysis that is observed as redistribution of cells expressing PAI-1. The area fraction of PAI-1 positive components correlates with clinical classification of AAA.
