Abstract 2606: Expression of Transforming Growth Factor-beta in the Aorta of Congenital Heart Disease
Background: The ascending aorta in congenital heart disease (CHD) sometimes dilates and requires surgical intervention. Medial abnormalities in the aorta have been implicated as a cause of the dilatation. In Marfan syndrome, overexpression of transforming growth factor (TGF)-beta has been detected in association with medial degeneration. The purpose of this study was to evaluate if overexpression of TGF-beta exists in the dilated aorta of CHD.
Methods: Intraoperative and necropsy specimen from the ascending aorta were obtained from 4 patients with CHD (tricuspid atresia, tetralogy of Fallot, double outlet right ventricle), 4 patients with congenital valvular aortic stenosis (AS), 4 patients with Marfan syndrome, and 4 patients without heart disease (control group). All patients in CHD, AS, and Marfan groups had abnormally dilated aorta. Medial abnormality was examined by light microcopy and expression of TGF-beta 1,2,3 was examined immunohistochemically.
Results: Light microscopy showed severe degeneration in Marfan group, moderate fragmentation of elastic fibers in CHD group, mild fragmentation of elastic fibers in AS group. TGF-beta 1 expression was detected in all groups; the expression was the greatest in the CHD group among 4 groups. The expression of TGF-beta 1 was also detected and was similar in the AS and Marfan group. The expression of TGF-beta 1 was weak in the control group. The expression of TGF-beta 2 was weak in all 4 groups. TGF-beta 3 was expressed similarly in all 4 groups.
Conclusion: There is overexpression of TGF-beta 1 in the dilated aorta of CHD, associated with medial abnormality. The overexpression of TGF-beta may contribute, at least in part, to the dilatation of the aorta in patients with CHD.