Analysis of potential biomarkers for diabetic kidney disease and non-diabetic kidney disease based on urinary metabolomics analysis.

BACKGROUND: Diabetic kidney disease (DKD) is a leading cause of chronic renal failure. However, not all patients with type 2 diabetes mellitus (T2DM) develop DKD. Some are diagnosed with non-diabetic renal disease (NDRD) or a combination of DKD and NDRD. Considering NDRD patients generally have a better prognosis than those with DKD, it is necessary to find biomarkers to distinguish them. In this study, we used urinary metabolomics to identify biomarkers of DKD and NDRD. METHODS: Urine samples were collected from patients diagnosed with DKD and NDRD. Differential metabolites between the two groups were screened by untargeted metabolomics, followed by Receiver Operating Characteristic (ROC) curve analysis, Pearson correlation analysis, and correlation with renal function to identify potential differential diagnostic markers. These markers were subsequently validated by targeted metabolomics. RESULTS: A total of 18 differential metabolites were identified by untargeted metabolomics. L-Tyrosine was significantly down-regulated in the DKD group. Moreover, our targeted metabolomics results showed a statistically significant difference in L-Tyrosine between the two groups (p < 0.05) and a trend consistent with the untargeted metabolomics results. CONCLUSION: L-Tyrosine showed consistent results in both untargeted and targeted metabolomics studies and was significantly down-regulated in the urine of the DKD group compared to the NDRD group. This suggests that decreased urinary L-Tyrosine could serve as a promising diagnostic biomarker for DKD, aiding in its differentiation from NDRD.