Aneurysm formation in proinflammatory, transgenic haptoglobin 2-2 mice

Area of Science:

• Vascular Biology
• Immunology
• Genetics

Background:

• Inflammation, particularly involving macrophages, is implicated in aneurysm development.
• The haptoglobin (Hp) 2-2 genotype is associated with a proinflammatory state, potentially influencing aneurysm formation.

Purpose of the Study:

• To investigate the role of inflammation in aneurysm formation using a murine model.
• To compare aneurysm development in transgenic, proinflammatory Hp2-2 mice versus wild-type Hp1-1 mice.

Main Methods:

• Carotid artery aneurysms were induced in Hp1-1 and Hp2-2 mice using elastase and angiotensin II.
• Aneurysm size was measured by outer and luminal circumference.
• Macrophage infiltration was quantified via immunohistochemistry.

Main Results:

• Aneurysms were significantly larger in Hp2-2 mice compared to Hp1-1 mice (P = .02 outer, P = .01 luminal circumference).
• Macrophage infiltration into the aneurysm wall was significantly higher in Hp2-2 mice (P < .001).

Conclusions:

• The proinflammatory Hp2-2 genotype is associated with increased aneurysm size and macrophage infiltration.
• Hp genotype may serve as a biomarker for predicting aneurysm progression.