GALECTIN-3 EXPRESSION IN HUMAN ATHEROSCLEROTIC LESIONS

The expression of galectin-3, a beta-galactoside-binding lectin, was s tudied in atherosclerotic lesions from specimens obtained from carotid endarterectomies, lower limb amputations, and thoracic aortas from au topsies of young adult trauma victims, Immunohistochemical staining wi th the monoclonal antibody M3/38 demonstrated the presence of galectin -3 in advanced atherosclerotic lesions from each of 13 cases of caroti d endarterectomy and 16 lower limb amputations and in the thoracic aor ta of 4 of 20 cases of trauma victim adults, Immunostaining did not de tect galectin-3 in umbilical cord and normal thoracic aorta arteries a nd limb veins. Dual immunostaining with monoclonal antibodies M3/38 fo r galectin-3 and clone 1A4 for smooth muscle alpha-actin or HAM56 for human macrophage antigen showed that galectin-3 was localized predomin antly in foam cells and macrophages and rarely (<5%) in the smooth mus cle cells of atherosclerotic lesions, The incidence of galectin-3-posi tive cells was higher in the carotid artery atherosclerotic lesions, w hich are richer in foam cells, than in the lower limb atherosclerotic lesions, which are more fibrotic. Reverse transcription polymerase cha in reaction show ed a significantly higher ratio of galectin-3/beta-ac tin transcripts in 20 atherosclerotic arteries compared with that of 5 umbilical cord arteries. Western blot analysis confirmed a higher lev el of galectin-3 in atherosclerotic carotid and lower limb arteries co mpared with that of umbilical cord arteries. The increased expression of galectin-3 in atherosclerotic lesions suggests the involvement of t his multifunctional protein in atherogenesis.