Circulating microRNA expression is reduced in chronic kidney disease

Background. MicroRNAs (miRNAs) are important regulators of gene expression, which have roles in renal development and disease. They exist in biological fluids including blood and urine and may have signalling roles and potential as disease biomarkers. Methods. We measured the levels of miRNAs in patients with different stages of chronic kidney failure including those receiving maintenance haemodialysis treatment. Results. In patients with severe chronic renal failure, circulating levels of total and specific miRNAs are reduced in comparison to patients with mild renal impairment or normal renal function. A strong correlation exists between detected circulating miRNAs and estimated glomerular filtration rate, and less strong correlations with other features of chronic kidney disease, such as anaemia and hyperparathyroidism. Conclusion. These findings have important implications for the use of circulating miRNAs as biomarkers in individuals with renal impairment and for the pathogenesis of uraemia.