Basic knowledge of interest Bioengineering of liver assist devices

urine. Hepatocytes, which are the predominant cell type within the liver, account for two-thirds of the liver mass. The liver is normally able to regenerate after acute injury and regain its function under appropriate physi-ological stimuli.1 However, when the normal regenera-tive process is compromised and the residual functional capacity of the damaged liver is unable to sustain life, liver failure occurs. Over 30000 patients die annually in the United States from liver failure. The two principal causes of the liver failure are cirrhosis and fulminant hepatic failure. Liver cirrhosis, whose etiology includes alcoholism and chronic hepatitis, is an irreversible process that occurs when fibrotic tissue replaces normal liver tissue as a result of chronic injury. Fulminant hepatic failure is a clinical syndrome, defined by impaired mental and neu-romuscular function, whose etiology includes chemical and viral hepatitis. It occurs as a result of massive hepa-tocyte necrosis and is the most severe manifestation of endstage liver disease, with mortality rates greater than 80%. Although there is currently no cure for liver fail-ure, orthotopic liver transplantation is the only clinically proven effective treatment for patients with endstage liver disease.2–6 In 2000, there were 4954 liver transplants performed in the United States (base