Thoracic aortic aneurysms were associated with increased MMP-9 and reduced TIMP-1 and TIMP-2 expression compared to controls, yielding a >3.5-fold greater MMP-9 to TIMP ratio.
Meta-Analysis
Does the protein expression of MMPs and TIMPs differ in the ascending aorta of patients with thoracic aortic aneurysms and bicuspid aortic valves compared to controls?
This meta-analysis demonstrates differential expression of MMPs and TIMPs in thoracic aortic aneurysms, with distinct profiles depending on the presence of a bicuspid aortic valve.
BACKGROUND: It is believed that the balance of matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs), in the aorta, play a critical role in aneurysm formation. The objective of this study was to perform a meta-analysis of studies reporting protein expression of MMPs and TIMPs in the ascending aorta of thoracic aortic aneurysms (TAA) cases and to examine this expression in persons with TAA and bicuspid aortic valves (BAV). METHODS: OvidSP Medline and EMbase were systematically searched for studies that were: human ascending TAA cases with measurement of MMP or TIMP protein expression in the aorta and a control group. A similar search was conducted for BAV compared to those with a normal or trileaflet aortic valve (TAV). RESULTS: Eight studies fulfilled the inclusion criteria. There was a significant increase in MMP-9 and no change in MMP-2, in the aorta from persons with TAA (N = 106) compared to control (N = 30). There was also a highly significant reduction in TIMP-1 and TIMP-2 in TAA (N = 93) compared to control (N = 24) resulting in a MMP-9 to TIMP-1 or TIMP-2 ratio over 3.5 fold greater than controls. There was a highly significant increase in MMP-2 but not MMP-9 in TAA with BAV (N = 112) compared to TAV (N = 53). There was a significant reduction for TIMP-1 in BAV compared to TAV but no change in TIMP-2, TIMP-3 or TIMP-4. CONCLUSIONS: These data suggest that MMP may be implicated in the pathogenesis of TAA and there is a differential expression with MMP-9 increased and TIMP-1 and -2 reduced in the most common forms of TAA. MMP-2 is increased and only TIMP-1 decreased in TAA with BAV compared to TAV.
Simon W. Rabkin (Thu,) conducted a meta-analysis in Thoracic aortic aneurysm. Thoracic aortic aneurysm (TAA) and bicuspid aortic valve (BAV) vs. Controls or trileaflet aortic valve (TAV) was evaluated on Protein expression of MMPs and TIMPs in the ascending aorta. Thoracic aortic aneurysms were associated with increased MMP-9 and reduced TIMP-1 and TIMP-2 expression compared to controls, yielding a >3.5-fold greater MMP-9 to TIMP ratio.