Matrix Metalloproteinases (MMPs),Neutrophil Gelatinase-associated Lipocalin (NGAL) Tissue and Plasma Levels and Aneurysms

An association between arterial aneurysms and matrix metalloproteinases (MMPs) has been described previously. MMPs regulate extracellular structural proteins and tissue remodeling. Neutrophil Gelatinase-associated Lipocalin (NGAL) is involved in the regulation of MMP activity. The aim of this work was to study the relationship between the levels of MMPs and NGAL and arterial aneurysms. In a multicenter, open label, parallel groups, prospective study, patients with aneurysmal disease were divided into two groups: Group I (with ruptured aneurysm) and Group II (with non-ruptured aneurysm). Healthy volunteer patients were also enrolled and represented the control group (Group III). The investigators enrolled 307 patients (Group I: 107, Group II: 200) with arterial aneurysm: 49 popliteal, 31 common femoral, 2 superficial femoral, 29 common iliac artery, 3 common carotid and 193 abdominal aorta. Finally, 11 healthy volunteer patients (9 males and 2 females, age range 40-70 year-old, median 56) were enrolled in Group III. Elisa test and Western blot analysis revealed greater levels of immunoreactive MMP-9 and NGAL in all patients with ruptured aneurysms, both central and peripheral aneurysms, and in the aneurismal vessels. These results provide important advances in the understanding of the natural history of arterial aneurysms. MMPs and NGAL play a role in development of arterial aneurysms and they may represent molecular markers for the prevention of aneurysmal rupture

In the present study, the analysis of MMPs levels in plasma and tissues in patients with aneurysmal lesions identified several patterns of protease activity. Levels of both MMP-9 and NGAL were increased in aneurismal vessels, while the patterns of MMP-9 and NGAL expression was very high in all patients with ruptured aneurysm, both central and peripheral. These results show: 1) the chronic and degenerative nature of the aneurysmal lesion which is associated with increased levels of inflammatory proteinases, like MMP-9; 2) the apparent pivotal role of MMP-9 and NGAL in the pathophysiologic processes which lead to the final stage of natural history of aneurysms; and 3) the ubiquitous distribution of MMP-9 and NGAL. The pattern increased expression of MMP-9 and NGAL appears to be specific for aneurysmal arteries and it is not dependent on the anatomic site of the lesion.