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Biology

Annual Report of Osaka University

Vascular Endothelial Dysfunction Resulting from L-arginine Deficiency in a Patient with Lysinuric Protein Intolerance

Although L-arginine is the only substrate for nitric oxide (NO) production, no studies have yet been reported on the effect of an L-arginine deficiency on vascular function in humans. Lysinuric protein intolerance (LPI) is a rare autosomal recessive defect of dibasic amino acid transport caused by mutations in the SLC7A7 gene, resulting in an L-arginine deficiency. Vascular endothelial function was examined in an LPI patient. Both NOx concentrations and endothelium-dependent vasodilation (EDV) were markedly reduced in the patient compared with those for the controls (Fig.1, 2). They became normal after an L-arginine infusion (Patient (Arg)). Positron emission tomography of the heart revealed ischemic changes in the patient, which was improved by the L-arginine infusion (Fig.3). In the LPI patient, we were able to show that an L-arginine deficiency causes vascular endothelial dysfunction via a decrease in NO production for the first time.

 

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