Preliminary study on the immunohistochemical expression of galectin-3 in hypertrophic hearts

Background: Galectin-3 overexpression is associated with fibroblastic proliferation and production of collagen, resulting in increased cardiac fibrosis and remodeling. The aim of the study was to investigate the expression of galectin-3 in hypertrophic hearts. We examined 19 surgical specimens taken from interventricular septum of 8 patients with Tetralogy of Fallot, four patients with aortic valve stenosis, one cardiac explant affected from dilated cardiomyopathy, and six myocardial biopsies of patients submitted to heart transplantation.
Methods: All the samples were routinely processed, stained with hematoxylineosin, trichromic stain, and elastic fiber stain, and selected by having the morphological features of myocardial hypertrophy: myocytolysis, nuclear pleomorphism, interstitial fibrosis.
Results: At immunohistochemistry, myocardial fibers showed cytoplasmic expression of galectin-3 in four patients with aortic valve stenosis (diffuse in three and mild in one), in one patient with cardiac explant (mild) and the 4/6 transplanted hearts (mild and focal in three and diffuse in one). The eight patients affected by Tetralogy of Fallot and two patients with transplanted hearts resulted negative.
Conclusions: The results agreed with the hypothesis that galectin-3 may play a role in cardiac hypertrophy; its expression in myocardial fibers is not related to the morphological aspects as suggested by the absence in pediatric cases. The presence of myocardial biopsies taken from transplanted hearts would suggest a possible role in predicting the clinical outcome of such patients.