Expression of fibrillin-1 in congenital bicuspid aortic valves

Objective: To detect the expression of fibrillin-1 in congenital bicuspid aortic valves, and to investigate the molecular mechanism of congenital bicuspid aortic valves.

Methods: Specimens of aortic valve were obtained from 12 pediatric patients with congenital bicuspid aortic valve, 11 boys and 1 girl, aged 16.7 (10 - 18), including 5 cases of aortic stenosis (AS), 8 of aortic insufficiency (AI), and 1 of AS and AI, undergoing valve replacement, 8 children who died accidentally without cardiovascular system and collagen system diseases, 6 boys and 2 girls, aged 9.1 (1 - 17), collected in autopsy [normal (tricuspid) aortic valve controls], and 18 pediatric patients of rheumatic valvular heart disease with diseased tricuspid aortic valves who underwent aortic valve replacement, 13 boys and 5 girls, aged 16.5 (12 - 18) (rheumatic valvular heart disease controls). HE staining and light microscopy were conducted. Immunohistochemistry was used to detect the expression of fibrillin-1 in the aortic valves.

Results: Microscopy showed that the tissue structure of the congenital bicuspid aortic valves was unclear with hyperplasia of fibrous tissue. The grey degree value of fibrillin-1 of the congenital bicuspid aortic valve group was 170 +/- 10, significantly lower than those of normal aortic valve group and diseased tricuspid aortic valve group (126 +/- 8 and 73 +/- 16 respectively, both P < 0.05). There were not significant difference in the grey degree value of fibrillin-1 among the patients of congenital bicuspid aortic valves with AS, AI, and AS + AI (167 +/- 6, 171 +/- 8, and 168 +/- 6 respectively).

Conclusions: The expression of fibrillin-1 is significantly reduced in congenital bicuspid aortic valves which may contribute to the morphological changes of the aortic valve leaflets and their resultant functional failure in congenital bicuspid aortic valves.