A thrombospondin-1 antagonist of transforming growth factor-β activation blocks cardiomyopathy in rats with diabetes and elevated angiotensin II

S Belmadani, J Bernal, CC Wei, MA Pallero… - The American journal of …, 2007 - Elsevier
S Belmadani, J Bernal, CC Wei, MA Pallero, L Dell'Italia, JE Murphy-Ullrich, KH Berecek
The American journal of pathology, 2007Elsevier
In diabetes and hypertension, the induction of increased transforming growth factor-β (TGF-
β) activity due to glucose and angiotensin II is a significant factor in the development of
fibrosis and organ failure. We showed previously that glucose and angiotensin II induce the
latent TGF-β activator thrombospondin-1 (TSP1). Because activation of latent TGF-β is a
major means of regulating TGF-β, we addressed the role of TSP1-mediated TGF-β activation
in the development of diabetic cardiomyopathy exacerbated by abdominal aortic coarctation …
In diabetes and hypertension, the induction of increased transforming growth factor-β (TGF-β) activity due to glucose and angiotensin II is a significant factor in the development of fibrosis and organ failure. We showed previously that glucose and angiotensin II induce the latent TGF-β activator thrombospondin-1 (TSP1). Because activation of latent TGF-β is a major means of regulating TGF-β, we addressed the role of TSP1-mediated TGF-β activation in the development of diabetic cardiomyopathy exacerbated by abdominal aortic coarctation in a rat model of type 1 diabetes using a peptide antagonist of TSP1-dependent TGF-β activation. This surgical manipulation elevates initial blood pressure and angiotensin II. The hearts of these rats had increased TSP1, collagen, and TGF-β activity, and cardiac function was diminished. A peptide antagonist of TSP1-dependent TGF-β activation prevented progression of cardiac fibrosis and improved cardiac function by reducing TGF-β activity. These data suggest that TSP1 is a significant mediator of fibrotic complications of diabetes associated with stimulation of the renin-angiotensin system, and further studies to assess the blockade of TSP1-dependent TGF-β activation as a potential antifibrotic therapeutic strategy are warranted.
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