Amplification of the genes that codify endothelin-1 and its receptors in rheumatic mitral valves

Cardiopathies are high prevalence conditions. Among them, rheumatic carditis is of high relevance in developing countries. Left cardiac chamber changes are associated to endothelial dysfunction and ET-1 levels increase. Pulmonary circulation is then affected, and not seldom leading to pulmonary hypertension (PH). However, the presence of ET-1 and its receptors in the mitral valve itself--promoting pulmonary vascular changes, with increased rheumatic valvular deformation--has not been discussed in the literature.

To determine the expression of endothelin gene and its receptors in rheumatic mitral valves through techniques of molecular genetics.

Twenty-seven patients submitted to mitral valve replacement had their valvular tissue examined to determine the presence of ET-1 genes and their A and B receptors. Histological and molecular analysis of the valves was performed (divided into M1, M2 and M3 fragments), with patients' clinical and epidemiological data collected. Patients were divided into 3 groups (mitral valvopathy, mitroaortic valvopathy, and reoperation patients).

The study showed endothelin-1 gene expression in 40.7% specimens and A receptor in all samples; receptor gene B had lower expression (22.2%).

All patients showed A receptor gene expression. No statistically significant difference was observed in regard to condition severity, expressed according to functional class, and subgroups (mitral valvopathy, mitroaortic valvopathy, and reoperation patients).