Acute kidney injury (AKI), regardless of its aetiology, can elicit persistent or permanent kidney tissue changes that are associated with progression to end-stage renal disease and a greater risk of chronic kidney disease (CKD). In other cases, AKI may result in complete repair and restoration of normal kidney function. The pathophysiological mechanisms of renal injury and repair include vascular, tubular, and inflammatory factors. The initial injury phase is characterized by rarefaction of peritubular vessels and engagement of the immune response via Toll-like receptor binding, activation of macrophages, dendritic cells, natural killer cells, and T and B lymphocytes. During the recovery phase, cell adhesion molecules as well as cytokines and chemokines may be instrumental by directing the migration, differentiation, and proliferation of renal epithelial cells; recent data also suggest a critical role of M2 macrophage and regulatory T cell in the recovery period. Other processes contributing to renal regeneration include renal stem cells and the expression of growth hormones and trophic factors. Subtle deviations in the normal repair process can lead to maladaptive fibrotic kidney disease. Further elucidation of these mechanisms will help discover new therapeutic interventions aimed at limiting the extent of AKI and halting its progression to CKD or ESRD.
Peritoneal M2 macrophage transplantation as a potential cell therapy for enhancing renal repair in acute kidney injury
