Clinical Effects of Topiroxostat on Renal and Endothelial Function in A Patient with Chronic Kidney Disease and Hyperuricemic Arteriolopathy: A Case Report.

Hyperuricemia is associated with the progression of chronic kidney disease (CKD) and cardiovascular diseases. Topiroxostat, a selective xanthine oxidase inhibitor, effectively reduces serum uric acid (UA) levels and urinary albumin excretion (UAE) in CKD patients. A 50-year-old Japanese man was referred to our hospital due to albuminuria and hyperuricemia, and renal biopsy showed a typical hyperuricemic arteriolopathy. Treatment with topiroxostat decreased serum UA levels (9.2 mg/dL at baseline to 6.4 mg/dL after 6 months), UAE (388 to 88 mg/g.cr), and urinary level of liver-type fatty acid-binding protein (28.8 to 19.8 µg/g.cr). Interestingly, topiroxostat treatment was associated with a trend towards improved flow-mediated dilation (5.4 to 5.8%). These results suggested that topiroxostat in CKD patients with hyperuricemia is potentially effective, not only for ameliorating renal damages but also for improving endothelial function beyond its UA-lowering action.