Role of microvesicles in acute kidney injury.

The main function of microvesicles (MVs) is signaling through specific interactions with target cells and transferring gene products. Therefore, they may participate in physiological and pathological processes. Gaining further insights into the molecular specificity of MVs has allowed identifying the cellular source and may provide new diagnostic tools in the future. Indeed, an increasing body of evidence indicates that MVs may offer prognostic information in various diseases such as chronic inflammation, cardiovascular and renal diseases, pathological pregnancy, tumors, and sepsis. The presence of MVs in body fluids makes them readily accessible. Their number, cellular origin, composition and function can be dependent on the state of the disease. In sepsis for example, activated endothelial cells may shed MVs that might trigger leukocyte and monocyte production and release pro-oxidant and inflammatory mediators. MVs from platelets may trigger disseminated intravascular coagulopathy. MVs are no doubt also involved in modulating immunity and future studies will clarify their functional role in negatively modulating the cell response. In addition, the recognition of the signals delivered by MVs may open new therapeutic strategies. The removal of harmful MVs from plasma may be beneficial in pathological conditions where MVs deliver thrombogenic and inflammatory signals. On the other hand, MVs derived from stem cells may reprogram altered functions in target cells suggesting that they could be exploited in regenerative medicine to repair damaged tissues. We will discuss the role of stem cell-derived MVs in the repair of acute kidney injury.