Lack of endothelial nitric oxide synthase accelerates ectopic calcification in uremic mice fed an adenine and high phosphorus diet.

Abstract Ectopic calcification is a risk of cardiovascular disease (CVD) in chronic kidney disease (CKD) patients, and impaired endothelial nitric oxide synthase (eNOS) is involved in the CKD complications. However, whether eNOS dysfunction is a cause of ectopic calcification in CKD remains to be elucidated. To address this issue, we investigated the role of eNOS on ectopic calcification in mice with renal injury caused by an adenine and high phosphorus (Ade + HP) diet. DBA/2J mice, a calcification-sensitive strain, were fed with Ade + HP for 3 weeks. Expression levels of eNOS -related genes were significantly reduced in their calcified aorta. C57BL/6J is a calcification-resistant strain, and wild-type mice showed mild calcified lesions in the aorta and kidney when given an Ade + HP for 4 weeks. In contrast, lack of eNOS led to the development of severe aortic calcification accompanied by increase of runt-related transcription factor 2, an osteo-chondrogenic marker. Elevated renal calcium deposition and tubular injury score were remarkable in mice lacking eNOS fed Ade + HP. Exacerbation of ectopic calcification by a lack of eNOS is associated with increased oxidative stress markers such as nicotinamide adenine dinucleotide phosphate oxidases. In conclusion, eNOS is critically important in preventing ectopic calcification. Therefore, the maintenance of eNOS is useful to reduce CVD events and to improve the prognosis of CKD patients.