Liver physiology and liver diseases in the elderly.

The liver experiences various changes with aging that could affect clinical characteristics and outcomes in patients with liver diseases. Both liver volume and blood flow decrease significantly with age. These changes and decreased cytochrome P450 activity can affect drug metabolism, increasing susceptibility to drug-induced liver injury. Immune responses against pathogens or neoplastic cells are lower in the elderly, although these individuals may be predisposed to autoimmunity through impairment of dendritic cell maturation and reduction of regulatory T cells. These changes in immune functions could alter the pathogenesis of viral hepatitis and autoimmune liver diseases, as well as the development of hepatocellular carcinoma. Moreover, elderly patients have significantly decreased reserve functions of various organs, reducing their tolerability to treatments for liver diseases. Collectively, aged patients show various changes of the liver and other organs that could affect the clinical characteristics and management of liver diseases in these patients.