Background: MicroRNAs (miRNAs), a family of endogenous small non-coding RNAs, are associated with the development of renal diseases. To clarify whether urinary miRNAs (UmiRNAs) can be used for the evaluation of renal disease, we examined the profiles of UmiRNAs in various renal diseases.
Methods: We extracted miRNAs from urine specimens of 5 healthy controls and 71 patients with renal diseases, and we examined the correlation between clinical and histological parameters and the profile of UmiRNAs by microarray analysis.
Results: The urinary concentration of miRNAs increased in patients with renal disease compared with healthy controls, and the levels correlated with urinary protein and the degree of glomerular sclerosis. The microarray analysis detected 83-137 distinct UmiRNAs. We observed 80-99 % of the miRNAs in both the healthy controls and the renal disease patients. The majority of UmiRNAs displayed higher signal intensity in renal disease patients than in healthy controls, including 39 miRNAs exhibiting signal intensities 100 times greater than in healthy controls. A different pattern of UmiRNAs was observed in each type of renal disease. A comparison of renal tissue and UmiRNAs revealed that the sample profiles were similar and that their signal intensity was significantly correlated.
Conclusion: This study demonstrated that UmiRNAs are correlated with renal pathological changes and that the profile of UmiRNAs presented different patterns corresponding to the type of renal disease. These results suggest that UmiRNAs can potentially be used as novel biomarkers for renal diseases.