AUTHOR=Staal Alexander H. J. , Cortenbach Kimberley R. G. , Gorris Mark A. J. , van der Woude Lieke L. , Srinivas Mangala , Heijmen Robin H. , Geuzebroek Guillaume S. C. , Grewal Nimrat , Hebeda Konnie M. , de Vries I. Jolanda M. , DeRuiter Marco C. , van Kimmenade Roland R. J. TITLE=Adventitial adaptive immune cells are associated with ascending aortic dilatation in patients with a bicuspid aortic valve JOURNAL=Frontiers in Cardiovascular Medicine VOLUME=10 YEAR=2023 URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2023.1127685 DOI=10.3389/fcvm.2023.1127685 ISSN=2297-055X ABSTRACT=Background

Bicuspid aortic valve (BAV) is associated with ascending aorta aneurysms and dissections. Presently, genetic factors and pathological flow patterns are considered responsible for aneurysm formation in BAV while the exact role of inflammatory processes remains unknown.

Methods

In order to objectify inflammation, we employ a highly sensitive, quantitative immunohistochemistry approach. Whole slides of dissected, dilated and non-dilated ascending aortas from BAV patients were quantitatively analyzed.

Results

Dilated aortas show a 4-fold increase of lymphocytes and a 25-fold increase in B lymphocytes in the adventitia compared to non-dilated aortas. Tertiary lymphoid structures with B cell follicles and helper T cell expansion were identified in dilated and dissected aortas. Dilated aortas were associated with an increase in M1-like macrophages in the aorta media, in contrast the number of M2-like macrophages did not change significantly.

Conclusion

This study finds unexpected large numbers of immune cells in dilating aortas of BAV patients. These findings raise the question whether immune cells in BAV aortopathy are innocent bystanders or contribute to the deterioration of the aortic wall.