Study on the diagnosis of gout with xanthine and hypoxanthine.

Hyperuricemia is the only biochemical index in the classification of acute gouty arthritis in American Rheumatism Association 1977 and the main basis of clinical diagnosis for most doctors. However, nearly half of the time gout occurs without hyperuricemia, especially in an acute attack，which leads to an urgent need to find a new substitute diadynamic criteria of gout. Xanthine and hypoxanthine, as precursors of uric acid, have been reported to be high in gout patients with hyperuricemia and presumed to be gout biomarkers. To further explore the possibility of xanthine and hypoxanthine to be gout biomarkers as substitutes for uric acid. A reversed-phase HPLC-UV method was employed for simultaneous quantitative detection of uric acid (UA), xanthine (X), and hypoxanthine (HX) in gout patients' (with and without hyperuricemia) and healthy persons' serum. The xanthine and hypoxanthine concentrations in gout patients with hyperuricemia and without hyperuricemia are higher than in healthy persons with a P < 0.001. This study supplements previous researches by confirming that xanthine and hypoxanthine are significantly elevated in gout patients' serum especially in patients' with normouricemia, which supported xanthine and hypoxanthine may have clinical application for the diagnosis of gout.

Wang Y ，Deng M ，Deng B ，Ye L ，Fei X ，Huang Z ... -  《-》

Quantification of uric acid, xanthine and hypoxanthine in human serum by HPLC for pharmacodynamic studies.

Cooper N ，Khosravan R ，Erdmann C ，Fiene J ，Lee JW ... -  《-》

Improved ultra-high performance liquid chromatographic method for simultaneous determination of five gout-related metabolites in human serum.

Creatinine and purines are gout-related metabolites commonly quantified by liquid chromatography coupled with ultraviolet and mass spectrometry. However, the high cost of liquid chromatography coupled with mass spectrometry hindered its extensive use in ordinary hospitals and clinical laboratories. Using the traditional liquid chromatography method, the full separation of these metabolites in complex biological samples is still not achieved. In this study, an improved ultra-high-performance liquid chromatography with ultraviolet spectroscopy method was reported for quantitative determination of five gout-related metabolites (i.e., creatinine, uric acid, hypoxanthine, xanthine, and inosine) in human serum within 10 min. A UHPLC system equipped with a hydrophilic C18 column was used to improve separation, shorten analysis time, and increase analysis throughput. The performance of the method was validated by evaluating linearity (squared correlation coefficient > 0.9991), recovery (92.8-100.0%, with relative standard deviation < 4.7%), accuracy (relative errors < 14.6%), precision (0.2-4.1% for intraday and 2.1-7.3% for interday) and stability (-14.1 to 8.3% in autosampler for 12 h and -13.3 to 2.2% for freeze-thaw cycles). This method was successfully applied to quantify gout-related metabolites in serum samples of healthy controls and gout patients, which was expected to be used in the clinical investigation of gout at different stages.

Kang L ，Liu J ，Zhang H ，Jiang M ，Jin Y ，Zhang M ，Hu P ... -  《-》

Renal excretion of hypoxanthine and xanthine in primary gout.

Puig JG ，Mateos FA ，Jiménez ML ，Ramos TH ... -  《AMERICAN JOURNAL OF MEDICINE》

Purine metabolism in women with primary gout.

Puig JG ，Mateos FA ，Miranda ME ，Torres RJ ，de Miguel E ，Pérez de Ayala C ，Gil AA ... -  《AMERICAN JOURNAL OF MEDICINE》