Nosology and Semiotics -- Acute kidney injury: definition and generalities.- Hormones -- Neurotransmitters and autonomous nervous system -- Cytokines, chemokines, inflammasomes, myokines and complement-related factors in acute kidney injury (AKI) -- Cell Adhesion and Cell Cycle Mediators -- Genetics and Epigenetics of Acute Kidney Injury -- Organ Crosstalk and Acute Kidney Injury -- Brain-Kidney Crosstalk in Acute Kidney Injury -- Lung-Kidney Crosstalk in Acute Kidney Injury -- Heart-Kidney Crosstalk in Acute Kidney Injury -- Gut-Kidney Crosstalk in Acute Kidney Injury -- Liver-Kidney Crosstalk in Acute Kidney Injury -- Muscle-Kidney Crosstalk in Acute Kidney Injury -- Placenta-Kidney Crosstalk in Acute Kidney Injury -- Renal Replacement Treatment and Crosstalk in Acute Kidney Injury -- Acute Kidney Injury and Organ Crosstalk in COVID-19 Infection.