INTRODUCTION AND AIMS: Severe acute kidney injury (AKI) is a major clinical problem that still has no established treatment.METHODS: We investigated the efficacy of cultured human peripheral blood mononuclear cells (PBMNCs) for AKI.Ischemia/reperfusion injury (IRI) was used to induce AKI in NOD/SCID mice.PBMNCs were isolated from healthy volunteers and cultured for 7 days in medium containing 5 vasculogenic factors.IRI-induced mice were divided into 3 groups and administered 1) 1 x 106 cultured PBMNCs (c-PBMNCs), 2) 1 x 106 non-cultured PBMNCs (nc-PBMNCs), or 3) vehicle without PBMNCs (control).PBMNCs or vehicle were injected 24 hours after induction of IRI, at which time AKI was thoroughly induced.Renal function, pathological change, homing of injected cells, peritubular capillary (PTC) loss were evaluated.Change of cell population by ex vivo culture were also evaluated by flow cytometry analysis.RESULTS: Blood urea nitrogen (BUN) and serum creatinine (sCr) 48 hours after cell injection dramatically improved in c-PBMNCs group compared with IRI control group (BUN, 36.164.3 mg/dL vs. 99.5639.4mg/dL; sCr, 0.2560.06mg/dL vs. 0.8960.19mg/dL), accompanied by improvement of tubular damages.Interstitial fibrosis 14 days after induction of IRI was also significantly improved in c-PBMNCs group compared with IRI control.Renoprotective effect noted in c-PBMNCs group was accompanied by reduction of PTC loss.All These effects were not shown in nc-PBMNCs group.The change in PBMNCs population by culture (significant increase in CD34þ cells , CD34þ/CD133þ cells, and CD206þ cells compared with nc-PBMNCs) and increased endothelial progenitor cell-colony forming potential might be one of the beneficial mechanisms for restoring AKI.

Acute kidney injury (AKI) is a common and potentially lethal complication in the hospitalized patients, with hypoxic injury being as a major cause. The loss of renal tubular epithelial cells (TEC), one of the AKI hallmarks, is potentially followed by tubular regeneration process orchestrated by the remaining uninjured TECs that undergo proliferation and migration. In this study, we used human primary TEC to investigate the initiation of tubular cell migration and associated cytoskeletal alterations in response to pharmacological HIF stabilization which resembles the pathophysiology of hypoxia. Tubular cells have been shown to migrate as cohorts in a wound healing assay. Importantly, cells of distal tubular origin moved faster than those of proximal origin. HIF stabilization impaired TEC migration, which was confirmed by live single cell tracking. HIF stabilization significantly reduced tubular cell migration velocity and promoted cell spreading. In contrast to the control conditions, HIF stabilization induced actin filaments rearrangement and cell adhesion molecules including paxillin and focal adhesion kinase. Condensed bundling of keratin fibers was also observed, while the expression of different types of keratins, phosphorylation of keratin 18, and the microtubule structure were not altered. In summary, HIF stabilization reduced the ability of renal tubular cells to migrate and led to cytoskeleton reorganization. Our data suggested an important involvement of HIF stabilization during the epithelial migration underlying the mechanism of renal regeneration in response to AKI.