Autophagy in renal tubular injury and repair.

Autophagy is a fundamental cellular process that maintains normal function and structure of the cell. It can be induced during stress and serves as an adaptive response for cell survival. Normal kidneys have high metabolic demands yet are relatively hypoxic, especially in the medulla and papilla. Injury or ageing aggravates metabolic perturbation and activates autophagy in many types of renal cells. In the kidney, tubular epithelial cells consume the most energy due to active transport mechanisms and therefore are the most susceptible to injuries from hypoxic or low-energy states. This brief review will summarize current understandings of the biological function and molecular regulation of epithelial autophagy during tubular injury and repair.