Micro-RNA expression in the urinary sediment of patients with chronic kidney diseases.

BACKGROUND: Evidence indicates that microRNAs (miRNA) play a role in the pathogenesis of chronic kidney diseases (CKD). We explored the possibility of using urinary miRNA as non-invasive biomarkers for CKD. METHODS: We quantified miRNA expression in urinary sediment of 56 CKD patients who underwent kidney biopsy. Patients were followed for 16.2 ± 15.5 months. RESULTS: Patients with diabetic glomerulosclerosis had lower urinary miR-15 expression, while those with IgA nephropathy had higher urinary miR-17 expression, than other diagnosis groups. Baseline proteinuria had significant inverse correlation with urinary expression of miR-15, miR-192, and miR-216a; baseline renal function correlated with urinary expression of miR-15, miR-17, miR-192, and miR-217. The rate of renal function decline correlated with urinary expression of miR-21 (r=0.301, p=0.026) and miR-216a (r=0.515, p < 0.0001). Patients with a high urinary expression of miR-21 and miR-216a had better dialysis-free survival than those with low expression (log rank test, p=0.005 and p=0.003, respectively). CONCLUSIONS: Urinary miR-21 and miR-216a expression correlated with the rate of renal function decline and risk of progression to dialysis-dependent renal failure. Our results suggest that urinary miRNA profiling has the potential of further development as biomarkers of CKD.

Carotid intima media thickness predicts cardiovascular diseases in Chinese predialysis patients with chronic kidney disease.

Patients with chronic kidney disease (CKD) have a high risk for cardiovascular disease. Ultrasound measurements of the intima media thickness (IMT) in the carotid arteries is a strong predictor for cardiovascular events in the general population and dialysis patients. However, it is unclear whether carotid IMT is useful for the prediction of cardiovascular events in predialysis patients with CKD. The prediction power of carotid ultrasonography for cardiovascular event, rate of renal function decline, and all-cause mortality was tested in a cohort of 203 Chinese patients with stages 3 to 4 CKD. The average IMT was 0.808 +/- 0.196 mm; 121 (59.6%) patients had atherosclerotic plaques visualized. IMT correlated with patient age (r = 0.373, P < 0.001), serum LDL level (r = 0.164, P = 0.021), Charlson's comorbidity score (r = 0.260, P < 0.001), and serum C-reactive protein (r = 0.279, P < 0.001). Carotid IMT was significantly higher in patients with diabetes than in those without diabetes (0.930 +/- 0.254 versus 0.794 +/- 0.184; P = 0.002). At 48 mo, the cardiovascular event-free survival was 94.4, 89.8, 77.7, and 65.9% for IMT quartiles I, II, III, and IV, respectively (log rank test, P = 0.006). By multivariate analysis with the Cox proportional hazard model, each higher quartile of IMT conferred 41.6% (95% confidence interval 6.4 to 88.4%; P = 0.017) excess hazard for developing cardiovascular event. The actuarial survival at 48 mo was 96.3, 98.0, 95.7, and 85.7% for IMT quartiles I, II, III and IV, respectively (log rank test, P = 0.127), and the difference was not statistically significant after Cox proportional hazard model to adjust for confounders. Carotid IMT did not correlate with the rate of renal function decline in these patients. Carotid IMT is a strong predictor of cardiovascular disease in Chinese predialysis patients and may be usefully applied for risk stratification in this group of patients.