High salt intake exacerbates aortic dissection through IL-17 pathway

Rationale— Aortic dissection (AD) is a fatal disease that occurs suddenly without preceding clinical signs or symptoms. It is desirable to prevent AD before the onset. Although high salt intake is an established risk factor for cardiovascular diseases, the relationship between high salt intake and AD has not been clarified. Although recent studies have shown that high salt intake promotes interleukin (IL)-17-dependent inflammation, it is unknown whether this mechanism is involved in the pathogenesis of AD. Objective— The purpose of this study was to investigate the effect of high salt challenge on AD and involvement of IL-17. Methods and Results— We used a mouse AD model that was induced by continuous infusion of -aminopropionitrile and angiotensin II. High salt challenge exacerbated AD lesion length compared to the mice without high salt challenge, which was abolished in IL-17 knockout mice. Unexpectedly, deletion of IL-17 resulted in the activation of Smad pathway, induction of synthetic phenotype of smooth muscle cells, remodeling of extracellular matrix in aortic tunica media, reduced stiffness of aortic walls, and less stress-induced activation of NFkB. Conclusions— These findings establish the worsening effect of high salt intake on AD that involves IL-17 pathway through the extracellular matrix metabolism. Salt restriction may represent a low-cost and practical way to reduce AD risk. Wild type C57BL/6 mice or IL-17-deicient mice were with or without high salt challenge by 1% NaCl as drinking water prior to and during 3 days of continuous infusion of BAPN and angiotensin II or vehicle. Three biological replicates were made in each of 8 experimental groups.