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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, OBJECTIVE, RESULTS. Meshes: Animals, Cell Survival, Cells, Cultured, Chemokines, Cytokines, Disease Models, Animal, Extracellular Matrix Proteins, Fibroblast Growth Factor 2, Fibroblasts, Male, Mice, Mice, Inbred C57BL, Mice, Mutant Strains, Myocardial Infarction, Myocarditis, Myocardium, Peptide Hydrolases, Recovery of Function, Rupture, Spontaneous, Syndecan-4, Ultrasonography, Up-Regulation, Ventricular Dysfunction, Left, Wound Healing.
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Does syndecan-4 prevent cardiac rupture and dysfunction after myocardial infarction? Context: Syndecan-4 (Syn4), a cell-surface heparan sulfate proteoglycan, has been detected in the infarct region after myocardial infarction (MI), but its functional significance has not been elucidated. We examined whether and how Syn4 regulates the cardiac healing process after MI. Although the heart in Syn4-deficient (Syn4(-/-)) mice was morphologically and functionally normal, Syn4(-/-) mice exhibited impaired heart function and increased mortality rate as a result of cardiac ruptures after MI. Cardiac ruptures in Syn4(-/-) mice were associated with reduced inflammatory reaction and impaired granulation tissue formation during the early phase of MI, as evidenced by reduced numbers of leukocytes, fibroblasts, myofibroblasts, macrophages, and capillary vessels, along with reduced extracellular matrix protein deposition in the infarct region after MI. Transforming growth factor-β1-dependent cell signaling was preserved, whereas cell migration, fibronectin-induced cell signaling, and differentiation into myofibroblasts were defective in Syn4(-/-) cardiac fibroblasts. We also found that Syn4 was involved in basic fibroblast growth factor-dependent endothelial cell signaling, cell proliferation, and tube formation. Finally, overexpression of the shed form of Syn4 before MI creation led to an increase in mortality due to cardiac rupture via its action as a dominant-negative inhibitor of endogenous Syn4 signaling, which suggested a protective role of Syn4 signaling in MI.
assistant
These results suggest that Syn4 plays an important role in the inflammatory response and granulation tissue formation, thereby preventing cardiac rupture and dysfunction after MI. Final Decision: yes