title: Spatial differences of matrix metalloproteinase-2 and matrix metalloproteinase-9 within abdominal aortic aneurysm wall and intraluminal thrombus.
abstract: Formation of an abdominal aortic aneurysm is a complex process involving aortic wall degradation. The matrix metalloproteinases (MMPs) mainly involved in this process are MMP-2 and MMP-9. Most aneurysms contain an intraluminal thrombus. It is suggested that the thrombus' thickness correlates with the risk of aneurysm rupture and may be a new prognostic factor. The purpose of the present study was to investigate enzyme protein levels in thick (A1) and thin (B1) segments of the thrombus and aneurysm wall sections A (adjacent to A1) and B (adjacent to B1). Aneurysm samples from one aneurism sac were collected from 36 patients that underwent aneurysm repair. MMP-2, MMP-9 and a tissue inhibitor of metalloproteinases (TIMP-1) were measured using enzyme-linked-immunosorbent assay of protein extract. MMP-9 concentrations were significantly higher in B1 samples compared with A1 (113.4 ± 118.0 versus 63.0 ± 61.2, P = 0.004), A(113.4 ± 118.0 versus 31.7 ± 30.0, P < 0.001) or B (113.4 ± 118.0 versus 39.5 ± 41.5, P < 0.001). Likewise MMP-9/TIMP-1 ratio was elevated in B1 compared with A1 (18.9 ± 27.8 versus 9.1 ± 10.6, P = 0.017), A (18.9 ± 27.8 versus 2.5 ± 2.2, P < 0.001) or B (18.9 ± 27.8 versus 3.6 ± 4.5, P < 0.001). MMP-2 and TIMP-1 were higher in A compared with A1 (18.4 ± 8.5 versus 7.2 ± 7.6, P < 0.001; 14.3 ± 5.9 versus 8.5 ± 5.4, P < 0.001, respectively) and B1 (18.4 ± 8.5 versus 5.2 ± 2.9, P < 0.001; 14.3 ± 5.9 versus 8.9 ± 4.9, P < 0.001, respectively) as well as in B compared with A1 (15.9 ± 7.3 versus 7.2 ± 7.6, P < 0.001; 13.0 ± 5.0 versus 8.5 ± 5.4, P < 0.001, respectively) and B1 (15.9 ± 7.3 versus 5.2 ± 2.9, P < 0.001; 13.0 ± 5.0 versus 8.9 ± 4.9, P = 0.003, respectively). There were significant correlations between thin thrombus TIMP-1 and thrombus thickness (β = -0.24, P = 0.021) and between thin thrombus MMP-9/TIMP-1 ratio and thrombus thickness (β = 1.75, P = 0.003). Our study has revealed that the presence of thrombi with thin segments in the aneurysm sac, associated with higher proteolytic activity, could possibly be used as a potential indicator of a rupture site.
authors.affiliation: Department of Laboratory Diagnostics, Pomeranian Medical University, Szczecin, Poland. asienn@pum.edu.pl.
authors.forename: A
authors.initials: A
authors.lastname: Siennicka
authors.affiliation: Department of Laboratory Diagnostics, Pomeranian Medical University, Szczecin, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Zuchowski
authors.affiliation: Department of Clinical and Molecular Biochemistry, Pomeranian Medical University, Szczecin, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Kaczmarczyk
authors.affiliation: Department of Vascular and General Surgery and Angiology, Pomeranian Medical University, Szczecin, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Cnotliwy
authors.affiliation: Department of Clinical and Molecular Biochemistry, Pomeranian Medical University, Szczecin, Poland.
authors.forename: J S
authors.initials: JS
authors.lastname: Clark
authors.affiliation: Department of Laboratory Diagnostics, Pomeranian Medical University, Szczecin, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Jastrzebska
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal / Q000378:metabolism*; D017544:Aortic Aneurysm, Abdominal / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008875:Middle Aged; D013927:Thrombosis / Q000378:metabolism*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism
chemical_list: C560822:TIMP1 protein, human; D019715:Tissue Inhibitor of Metalloproteinase-1; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9