In a mouse model of aortic valve stenosis, researchers assayed SMAD2/3 phosphorylation in circulating leukocytes and platelet-leukocyte aggregates and found that p-SMAD2/3 staining was more intense in leukocytes of hypercholesterolemic mice that developed aortic valve stenosis, suggesting increased circulating active TGF-β1 levels [56]. Here, SMAD2 is linked to stricture.