Upregulated sulfatase and downregulated MMP-3 in thoracic aortic aneurysm

Background. Thoracic aortic aneurysm (TAA) formation is accompanied by degradation of extracellular matrix components (EMC). Numerous matrix metalloproteinases (MMPs) have been implicated in the process, but the involvement of MMP-3 remains unclear. Additionally, the changes in proteoglycan (PG) structure can alter the signal transduction pathways in TAA, though the enzymatic systems which originate them are not fully understood. Objectives. To measure MMP-3 and sulfatase levels in aneurysmal tissue, comparing them with non-aneurysmal vessels, and to investigate possible correlations with patients' serum levels in order to evaluate their potential usefulness in aiding aneurysm detection and monitoring. Material and methods. The study included 74 patients (TAA: n = 42; control group: n = 32). Sulfatase activity was measured colometrically and MMP-3 levels were measured immunoenzymatically. Results. Sulfatase activities were higher (p = 0.03) and MMP-3 concentrations lower (p = 0.014) in aneurysmal tissue than in normal aortic tissue. Medium-sized dilatations were associated with lower tissue MMP-3 concentrations than small dilatations (p = 0.033). No differences in sulfatase activity or MMP-3 concentration in the serum of TAA patients were observed in comparison with the controls. The serum and tissue levels of MMP-3 were correlated (r = 0.41; p < 0.001). The serum levels of MMP-3 were significantly lower in the female patients than in the male patients (p = 0.006). Conclusions. Our studies confirmed the lower MMP-3 levels in aneurysmal tissue, but the lack of a statistically confirmed reduction of MMP-3 in the blood serum seems to preclude its usefulness for diagnostic purposes. Our study points to the differences in MMP-3 behavior between TAA and abdominal aortic aneurysms. Significantly higher sulfatase activity in TAA tissue suggests a possible impact of sulfatase on signal transduction pathways involved in aneurysm formation.