Kang Z, et al. - Whether or not remote ischemic pre-conditioning (RIPC) has a renoprotective effect in children with congenital heart disease undergoing cardiopulmonary bypass (CPB), was determined presuming that it may be related to the up-regulation of microRNA-21 (miR-21). A protective effect of RIPC on the kidney was reported in this patient population. This finding may be associated with the up-regulation of miR-21 and down-regulating inflammatory mediators, such as tumor necrosis factor-α.