Critical role of endogenous thrombospondin-1 in preventing expansion of healing myocardial infarcts
| Autor: | Sandra B. Haudek, Oliver Dewald, Lloyd H. Michael, Pawel Zymek, Nikolaos G. Frangogiannis, Jack Lawler, Anna Koerting, Guofeng Ren, Mark L. Entman, Kim Winkelmann |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Pathology
medicine.medical_specialty Angiogenesis Myocardial Infarction Inflammation Extracellular matrix Thrombospondin 1 Mice Dogs Physiology (medical) Medicine Animals Regeneration RNA Messenger Mice Knockout Thrombospondin Extracellular Matrix Proteins business.industry Matricellular protein Granulation tissue medicine.disease Cell biology Up-Regulation Disease Models Animal medicine.anatomical_structure Gene Expression Regulation Reperfusion Injury Endothelium Vascular medicine.symptom Chemokines Cardiology and Cardiovascular Medicine business Reperfusion injury |
| Zdroj: | Circulation. 111(22) |
| ISSN: | 1524-4539 |
| Popis: | Background— Matricellular proteins are extracellular matrix proteins that do not contribute directly to tissue integrity but are capable of modulating cell function. We hypothesized that the matricellular protein thrombospondin (TSP)-1, a potent inhibitor of angiogenesis and activator of transforming growth factor (TGF-β), is induced in healing myocardial infarcts and plays a role in suppressing the postinfarction inflammatory response, inhibiting local angiogenesis, and limiting expansion of granulation tissue into the noninfarcted area. Methods and Results— We used a canine and a murine model of reperfused infarction. TSP-1 mRNA was induced in canine infarcts after 1 hour of ischemia and 3 to 7 days of reperfusion. TSP-1 protein showed a strikingly selective localization in the extracellular matrix, microvascular endothelium, and a subset of mononuclear cells of the infarct border zone after 5 to 28 days of reperfusion. Isolated canine venous endothelial cells showed low-level constitutive expression of TSP-1 mRNA, which was markedly induced by TGF-β, and basic fibroblast growth factor. Murine infarcts also had marked TSP-1 deposition in the border zone. Infarcted TSP-1 −/− mice exhibited sustained upregulation of the chemokines monocyte chemoattractant protein-1, macrophage inflammatory protein-1α, and interferon-γ–inducible protein-10/CXCL10 and the cytokines interleukin-1β, interleukin-6, and TGF-β, suggesting an enhanced and prolonged postinfarction inflammatory response. In addition, TSP-1 −/− mice had markedly increased macrophage and myofibroblast density in infarcts and in remodeling noninfarcted myocardial areas neighboring the myocardial scar, suggesting expansion of granulation tissue formation into the noninfarcted territory. TSP-1 −/− animals had more extensive postinfarction remodeling than wild-type mice, although infarct size was similar in both groups. Conclusions— The infarct border zone may be capable of modulating the healing process through its unique extracellular matrix content. The selective endogenous expression of TSP-1 in the infarct border zone may serve as a “barrier,” limiting expansion of granulation tissue and protecting the noninfarcted myocardium from fibrotic remodeling. |
| Databáze: | OpenAIRE |
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