gms | German Medical Science

Introduction: Calpain-1 and Calpain-2 are acute phase proteins involved in proinflammatory processes. Activation of the Calpain family has been related to vessel wall degradation in animal models, and correlated with histological alterations in the dilated aorta in Marfan patients. The aim of our study was to investigate the aortic expression of Calpain-1 and Calpain-2 and correlate this expression with the local macrophage infiltration in patients with aortic aneurysms.

Material and methods: Expression of Calpain 1 and 2 (CAL1; CAL2) was assessed by real-time PCR and immunohistochemistry on the aortic wall of patients (n=10) with aneurysm of the ascending aorta (AAA) undergoing cardiac surgery. Local macrophage infiltration was assessed by RT-PCR and immunohistochemistry (CD163-Staining). A group consisting of aortic samples from patients without dilation of the aorta undergoing coronary by-pass grafting served as control. Statistical analysis was done with unpaired T-test.

Results: Expression of CAL1 was significantly increased in the AAA group in comparison to control (AAA 22.69 ± 1.5 vs. Control 15.48 ± 1; p< 0.001). However, expression of CAL2 was similar in dilated and not-dilated aortas (AAA 23.78 ± 1.5 vs. Control 21.30 ± 1.4; p=0.2). There were no differences regarding macrophage infiltration between the groups (AAA 13.58 ± 2.3 vs. Control 10.04 ± 1.4; p= 0.1). A correlation between the expression of proteins of the Calpain family and local inflammation was not observed.

Conclusion: Our results demonstrate a relationship between the Calpain family and the dilation of the ascending aorta, mediated through CAL1 and not CAL2. Lack of correlation between local macrophage infiltration and Calpain expression suggests a cellular-independent mechanism in the development of local inflammation in aortic aneurysms.