A selective antagonist of prostaglandin E receptor subtype 4 attenuates abdominal aortic aneurysm

Abdominal aortic aneurysm ( AAA ) is a progressive disease that has an increasing prevalence with aging, but no effective pharmacological therapy to attenuate AAA progression is currently available. We reported that the prostaglandin E receptor EP 4 plays roles in AAA progression. Here, we show the effect of CJ ‐42794, a selective EP 4 antagonist, on AAA using two mouse models (angiotensin II ‐ and CaCl 2 ‐induced AAA s) and human aortic smooth muscle cells isolated from AAA tissue. Oral administration of CJ ‐42794 (0.2 mg/kg per day) for 4 weeks significantly decreased AAA formation in ApoE −/− mice infused with angiotensin II (1  μ g/kg per min), in which elastic fiber degradation and activations of matrix metalloproteinase ( MMP )‐2 and MMP ‐9 were attenuated. Interleukin‐6 ( IL ‐6) proteins were highly expressed in the medial layer of angiotensin II ‐induced mouse AAA tissues, whereas this expression was significantly decreased in mice treated with CJ ‐42794. AAA formation induced by periaortic CaCl 2 application in wild‐type mice was also reduced by oral administration of CJ ‐42794 for 4 weeks. After oral administration of CJ ‐42794 beginning 2 weeks after periaortic CaCl 2 application and continuing for an additional 4 weeks, the aortic diameter and elastic fiber degradation grade were significantly smaller in CJ ‐42794‐treated mice than in untreated mice. Additionally, in smooth muscle cells isolated from human AAA tissues, stimulation of CJ ‐42794 inhibited PGE 2 ‐induced IL ‐6 secretion in a dose‐dependent manner and decreased PGE 2 ‐induced MMP ‐2 activity. These data suggest that inhibition of EP 4 has the potential to be a pharmacological strategy for attenuation of AAA progression.