Vascular and circulating microRNAs in renal ischaemia-reperfusion injury.

Ischaemia-reperfusion (I/R) injury of the kidney is a major cause of acute kidney injury. It may result in worsening or even loss of organ function. Transient occlusion of the renal vessel is followed by a reperfusion period, which induces further tissue damage by release of reactive oxygen and nitrogen species. Ischaemia-reperfusion injury of the kidney may be associated with surgical interventions in native kidneys and is also a common and unavoidable phenomenon in kidney transplantation. MicroRNAs are fascinating modulators of gene expression. They are capable of post-transcriptional silencing of genetic information by targeting the 3'-untranslated region of mRNAs, culminating in a suppression of protein synthesis or an increase in mRNA degradation. They might therefore be useful diagnostic and therapeutic entities during renal I/R injury; for instance, miR-21 has been shown to be enriched in kidney tissue in mice and humans with acute kidney injury. Interestingly, most recent literature suggests that modulation of vascular microRNAs might result in the amelioration of kidney function during renal I/R injury. To that end, miR-126 and miR-24, which have been demonstrated to be highly enriched in endothelial cells, were therapeutically modulated and shown to ameliorate renal I/R injury in mice. MicroRNAs in plasma, urine or enriched in microvesicles have been shown to serve as non-invasive tools for disease monitoring and to have potential impact on downstream mechanisms in recipient cells. This review highlights the latest developments regarding the role of microRNAs in renal I/R injury.