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Background: Acute aortic dissection (AAD) is associated with degeneration of the aortic media and accompanied by vascular extracellular matrix (ECM) remodeling. Recently, a disintegrin and metalloproteinase with thrombospondin type 1 motifs-5 (ADAMTS-5) has been reported to be involved in ECM remodeling and vascular diseases. The aim of this study was to examine ADAMTS-5 levels in AAD patients and investigate the underlying mechanisms. Methods: Aortic tissue samples were collected from normal donors and AAD patients, and the expression of ADAMTS-5 was analyzed in all aortic tissues. In addition, plasma levels of ADAMTS-5, matrix metalloproteinase (MMP)-2 and MMP-9, and tumor necrosis factor-α (TNF-α) were measured in repeated samples from AAD patients and compared to the non-AAD (NAD) group. In addition, we investigated the effects of ADAMTS-5 in smooth muscle cell (SMC) apoptosis. Results: The results showed that ADAMTS-5 expression was significantly reduced in the aortas of AAD patients and that SMCs were the main source of ADAMTS-5. In addition, the plasma ADAMTS-5 level was lower, but plasma MMP-2, MMP-9, and TNF-α levels were increased in the AAD patients. Multivariate linear regression analyses showed that a decreased ADAMTS-5 level in patients was independently associated with an increased risk of AAD. Furthermore, recombinant human ADAMTS-5 significantly ameliorated angiotensin (Ang II)-evoked SMC apoptosis. Conclusions: ADAMTS-5 shows promise as a novel potential biomarker for AAD, and regulation of SMC is a possible mechanism for the effects of ADAMTS-5.

Background Previous studies have shown that thrombospondin 1 (TSP-1) is involved in cardiovascular diseases, such as atherosclerosis and abdominal aortic aneurysm. However, TSP-1 expression levels in human aortic dissection (AD) remain unknown. Methods TSP-1 levels were detected in aortas collected from control subjects and AD patients. The TSP-1, interleukin (IL) 6, matrix metalloproteinase (MMP) 2, and MMP9 levels in plasma from non-AD patients and AD patients were measured. In addition, the effects of recombinant mouse TSP-1 protein on macrophage differentiation and smooth muscle cell (SMC) apoptosis were investigated. Results Compared with the aortas from control subjects, aortas from AD patients showed a significant increase in TSP-1 expression, especially in the torn sections. SMCs and endothelial cells produced TSP-1, but SMCs were the main source. TSP-1, IL-6, MMP2, and MMP9 levels were higher in AD patients than in non-AD patients, and plasma IL-6, MMP2, and MMP9 levels were positively correlated with TSP-1 levels in AD patients. Simple linear regression analysis and multivariate linear regression analysis showed that TSP-1 levels were independently correlated with the onset of AD. In cultured cells, recombinant mouse TSP-1 further increased inducible nitric oxide synthase (iNOS) mRNA expression in angiotensin (Ang) II-treated macrophages, whereas it reduced B-cell lymphoma-2 (Bcl2) mRNA levels and increased Bcl2-associated X protein (Bax) mRNA levels in Ang II-treated SMCs. Conclusions TSP-1 level is significantly increased in AD patients and might participate in AD via promoting classically activated macrophage (M1) macrophage differentiation and SMC apoptosis.