Elevated Levels of miR-155 in Blood and Urine from Patients with Nephrolithiasis

BACKGROUND Both circulating and urinary miRNAs may represent a potential noninvasive molecular biomarker capable of predicting chronic kidney disease, and, in the present study, we will investigate the serum and urinary levels of miR-155 in patients with nephrolithiasis. METHODS Serum and urinary levels of miR-155 are quantified in 60 patients with nephrolithiasis; the result was compared to 50 healthy volunteers. Estimated glomerular filtration (eGFR) was calculated and, by simple regression analysis, the correlations of miR-155/eGFR and miR-155/CRP (C-reactive protein) levels were analyzed as well. RESULTS The median levels of serum and urinary levels of miR-155 are significantly higher in nephrolithiasis patients than in controls. eGFR inversely correlates with urinary level of miR-155; CRP positively correlates with urinary miR-155. Urinary level of miR-155 inversely correlates with urinary expression of interleukin- (IL-) 1β, IL-6, and tumor necrosis factor- (TNF-) α and positively correlates with urinary expression of regulated upon activation, normal T-cell expressed, and secreted (RANTES). CONCLUSION Serum and urinary levels of miR-155 were significantly elevated in patients with nephrolithiasis, and the upregulation of miR-155 was correlated with decline of eGFR and elevation of CRP. Our results suggested that miR-155 might play important roles in the pathophysiology of nephrolithiasis via regulating inflammatory cytokines expression. Further study on the molecular pathogenic mechanism and larger scale of clinical trial are required.