Increased circulating trimethylamine N-oxide contributes to endothelial dysfunction in a rat model of chronic kidney disease
- Department of Cardiology, Shengjing Hospital of China Medical University, 36 Sanhao Street, Heping District, Shenyang, Liaoning, 110004 (China)
Highlights: • Circulating TMAO is elevated in chronic kidney disease. • Elevated TMAO in chronic kidney disease impairs endothelial function. • Elevated TMAO in chronic kidney disease reduces vascular eNOS activity. • Elevated TMAO in chronic kidney disease causes vascular oxidative stress. • Elevated TMAO in chronic kidney disease induces vascular inflammation. Chronic kidney disease (CKD) is strongly associated with increased cardiovascular risk. Impaired endothelial function, a key initiating step in the pathogenesis of cardiovascular disease, has been reported in patients with CKD, but the mechanisms responsible for endothelial dysfunction in CKD remain elusive. Emerging evidence reveals that trimethylamine-N-oxide (TMAO), a gut microbiota-generated metabolite, is involved in the pathogenesis of many cardiovascular diseases. Circulating TMAO is elevated in CKD. Here we tested the hypothesis that elevated TMAO plays a contributory role in the pathogenesis of endothelial dysfunction in CKD. Rats underwent 5/6 nephrectomy to induce CKD or sham operation, and were treated with 1.0% 3,3-Dimethyl-1-butanol (DMB, an inhibitor of trimethylamine formation) or vehicle. Eight weeks after nephrectomy and DMB treatment, circulating TMAO levels were markedly elevated in CKD-vehicle rats compared with sham-vehicle rats, but were reduced in CKD-DMB rats. Acetylcholine-induced endothelium-dependent vasodilation was impaired in CKD-vehicle rats compared with sham-vehicle rats as indicated by reduced maximal relaxation (E{sub max}) and decreased area under the curve (AUC). E{sub max} and AUC were both normalized in CKD-DMB rats. No difference in sodium nitroprusside-induced endothelial-independent vasodilation was observed across groups. Molecular studies revealed that endothelial nitric-oxide synthase activity was decreased, while superoxide production and proinflammatory cytokine expression were increased in the aorta of CKD-vehicle rats compared with sham-vehicle rats. Of note, the abnormalities in above molecular parameters were completely restored in CKD-DMB rats. These results suggest that CKD elevates circulating TMAO levels, which may reduce eNOS-derived NO production by increasing vascular oxidative stress and inflammation, contributing to CKD-associated endothelial dysfunction and cardiovascular disease.
- OSTI ID:
- 23134390
- Journal Information:
- Biochemical and Biophysical Research Communications, Vol. 495, Issue 2; Other Information: Copyright (c) 2017 Elsevier Inc. All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
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