Timo Paavonen, Eetu Niinimaki, Ville Pynnonen, Ivana Kholova, Ari Mennander
Department of Pathology, Fimlab and University of Tampere, Finland
DOI: http://dx.doi.org/10.18053/jctres.aecvp2016.022
Background and aim: Most aortic dissections occur in the outer third of the media close to the adventitia. This site is characterized by vasa vasorum that participates in the nutrition of the aortic wall. The significance of angiogenesis in the risk of aortic pathogenesis is under discussion. Methods: Tissue samples from dilated ascending aortic wall (more than 5.5 cm) resection biopsies of 35 patients undergoing surgery were obtained and processed for histology. H&E- and van Gieson-staining together with immunohistochemistry for CD31 (endothelial cells), T/B-lymphocytes, plasma cells, macrophages, and cell proliferation were performed. Results: Seventeen patients had ascending aortic dissection (AD+), while 18 patients were classified to have dilated aortic wall (AD–) upon histopathology. The intensity of adventitial and medial inflammation was increased in AD+ specimens compared to AD– specimens. The media and the intima showed increased mitotic activity in AD+ tissue compared to AD– tissue. The outer third layer of the media at the vicinity of the adventitia expressed increased number of CD31-positive vessels in AD+ specimens compared to AD– specimens (5.7 ± 1.3 vs 2.4 ± 0.7, p < 0.016). Conclusions: Local medial endothelial activity indicates active remodeling of the aortic wall susceptible to AD. The initiation of dissection may be predicted by investigating the aortic wall for inflammation and angiogenesis by endothelial activation of newly formed capillaries of the aortic wall.
Email: timo.paavonen@uta.fi
