Immunolocalisation of fibrin in coronary atherosclerosis: implications for necrotic core development

Area of Science:

• Cardiovascular Pathology
• Atherosclerosis Research
• Immunohistochemistry

Background:

• Intraplaque hemorrhage is linked to necrotic core expansion in atherosclerotic plaques.
• The role of fibrin in different stages of plaque progression requires further investigation.

Purpose of the Study:

• To investigate the presence and localization of fibrin within human coronary artery plaques across various stages of development.
• To correlate fibrin deposition with intraplaque neovascularization and red blood cell breakdown.

Main Methods:

• Human coronary artery sections (n=74) were analyzed using immunohistochemistry for fibrin II, glycophorin A (red blood cell marker), and CD31 (endothelial marker).
• Plaques were categorized into distinct American Heart Association (AHA) grades, including adaptive intimal thickening (AIT), intimal xanthomas, pathologic intimal thickening (PIT), fibroatheromas (FA), and thin cap fibroatheromas (TCFA).

Main Results:

• Fibrin was largely absent in early plaque stages (AIT, PIT) but present in early fibroatheroma cores.
• Late fibroatheromas and thin cap fibroatheromas showed significant intracore fibrin deposition.
• Intimal vasa vasorum counts correlated positively with fibrin scores, with minimal red cell breakdown observed in many fibrin-positive cores.

Conclusions:

• Fibrin deposition in necrotic cores is associated with increased intraplaque vasa vasorum and precedes overt intraplaque hemorrhage.
• Fibrin may contribute to the transition from pre-atheroma to advanced atheroma stages.