Objective To identify primary gout biomarkers. Methods Isobaric tags for relative and absolute quantitation (iTRAQ) technique combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to screen differentially expressed proteins, and to identify potential biomarkers by analysis of the biological process, cellular components, molecular functions, KEGG pathways and protein-protein interactions. Difference between two groups were measured byt test. Results We identified 95 differentially expressed proteins (50 up-regulated proteins and 45 down-regulated proteins, respectively), and 20 significant KEGG pathways. Among them, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), α-enolase (ENOA), phosphoglycerate kinase (PGK1), glucose-6-phosphate isomerase (G6PI) and moesin might play a role in the pathogenesis of primary gout. Conclusion iTRAQ technology can detect differentially expressed proteins from proteome, provides a strong theoretical basis for the study of biomarkers and evidence for the mechanisms in primary gout. However, further studies are needed.

Objective:To investigate the significance of serum fibroblast growth factor 19 (FGF19), Klotho and fibroblast growth factor receptor 4 (FGFR4) protein expression in patients with primary biliary cirrhosis (PBC).Methods:Sixty-three patients with PBC who received treatment in Ningbo Huamei Hospital, University of Chinese Academy of Sciences between August 2017 and July 2020 were included in the PBC group. An additional 51 healthy patients who concurrently received physical examination in the same hospital were included in the control group. Serum FGF19, Klotho and FGFR4 protein expression were determined by enzyme linked immunosorbent assay.Results:Serum FGF19 and FGFR4 protein in PBC group were (178.86 ± 21.28) ng/L and (2.96 ± 0.47) ng/L, respectively, which were significantly higher than those in the control group [(69.93 ± 12.12) ng/L, (1.21 ± 0.35) ng/L, t = 32.51, 27.98, both P < 0.05]. Klotho protein expression in the PBC group was significantly lower than that in the control group [(3.25 ± 0.89) μg/L vs. (9.67 ± 1.53) μg/L, t = 22.08, P < 0.05]. Serum levels of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase in the PBC group were (84.25 ± 13.24) U/L, (71.82 ± 10.35) U/L, (278.93 ± 32.45) U/L, respectively, which were significantly higher than those in the control group [(23.76 ± 3.42) U/L, (23.10 ± 4.53) U/L, (76.81 ± 16.36) U/L, t = 31.75, 31.26, 40.48, all P < 0.05]. The receiver operating characteristic curve analysis showed that the sensitivity and specificity of FGF19 in the diagnosis of PBC were 76.67% and 61.90%, respectively, they were 58.82% and 66.67% for Klotho protein diagnosis, 54.55% and 76.67% for FGFR4 protein. Pearson analysis revealed that there was a positive linear relationship between FGF19 and FGFR4 protein ( r = 0.78, P < 0.05), while there was a negative linear relationship between Klotho protein and FGFR4 protein ( r = -0.72, P < 0.05). Conclusion:In patients with PBC, serum FGF19 and FGFR4 protein levels are increased, while Klotho protein level is decreased. There is a positive linear relationship between FGF19 and FGFR4 protein, and there is a negative linear relationship between Klotho protein and FGFR4 protein. This study is highly innovative and scientific.