Emel Isiktas Sayilar, Mustafa Gullulu, Ercan Tuncel, Hande Peynirci, Adem Alemdar, Berrin Tunca, Unal Egeli, Gulsah Cecener, Murat Bayindir and Gokhan Cosgun
Aims: To evaluate the potential of urinary miR-451 as a biomarker at different stages of diabetic nephropathy. Methods: A total of 45 subjects having stage 3 chronic kidney disease (n=15) or stage 5 chronic kidney disease (n=15) and 15 healthy volunteers were included. Data on patient demographics, laboratory findings [creatinine, estimated glomerular filtration rate, urinary protein excretion] target genes and functions of the selected MicroRNAs associated with diabetic nephropathy and fold differences in the level of MicroRNA expression in blood and urine and the correlation of urine and plasma MicroRNA expression with estimated glomerular filtration rate were recorded. Results: MiR-195 expression level among stage 3 chronic kidney disease patients was higher in plasma samples compared to the control group, while it was significantly lower in the urine samples (p=0.036). In the stage 5 chronic kidney disease patient group, while the expression level was significantly higher in the plasma samples (p=0.005), urine sample expression was lower but not significantly different than the control group. Compared to the controls, miR-451 expression level was higher in the plasma samples of stage 3 chronic kidney disease patients, but significantly lower in the urine samples (p=0.019). Among the stage 5 chronic kidney disease patients, there was significantly higher level of expression in plasma samples (p=0.007) and significantly lower expression in urine samples (p=0.022) than the control group. Conclusions: Our study is original with its investigation of MicroRNA expressions at different stages of chronic kidney disease. Especially the statistically significant changes in the expression of miR-195 and miR-451 make these MicroRNAs come forward as good noninvasive biomarker candidates.