Relaxin and Matrix Metalloproteinase-9 in Angiotensin II-Induced Abdominal Aortic Aneurysms.

BACKGROUND

This study determined whether relaxin or matrix metalloproteinase (MMP)-9 influences angiotensin II (AngII)-induced abdominal aortic aneurysms (AAA).

METHODS AND

RESULTS

Male C57BL/6 or apolipoprotein E-/-mice were infused with AngII with or without relaxin. Relaxin did not influence AngII-induced AAA in either mouse strain. Infusion of AngII reduced, but relaxin increased, MMP-9 mRNA in macrophages. We then determined the effects of MMP-9 deficiency on AAA in apolipoprotein E-/-mice. MMP-9 deficiency led to AAA formation in the absence of AngII, and augmented AngII-induced aortic rupture and AAA incidence.

CONCLUSIONS

MMP-9 deficiency augmented AngII-induced AAA.