Bioartificial liver based on porcine hepatocyte: in vitro functional assessment

Intrahepatic biliary lesions after orthotopic liver transplantation

Intrahepatic biliary lesions (IBL) are rare (2-9%) after orthotopic liver transplantation (OLT). The aim was to evaluate the incidence, etiology and outcome. In nine years, a total 532 OLTs were performed in 481 patients. Twenty-four patients developed IBL. Eight were due to HAT, seven to ABOI, three to CDR and six to PI. The time until diagnosis of HAT is longest in patients (14+/-6) with IBL. ABOI is another cause of IBL. CDR is a rare cause of IBL, however when it takes place, patients must undergo Rtx. Finally, PI is a relevant cause of IBL. In order to suppress the incidence of IBL we should consider 1) the systematic use of Doppler-Ultrasound; 2) emergency reoperation of patients with HAT, 3) avoid ABOI in OLT; 4) Rtx in cases of CDR, and 5) OLT should still be performed as an emergency procedure.

Artificial liver support devices for fulminant liver failure

Artificial liver-support devices attempt to bridge patients with fulminant hepatic failure until either a suitable liver allograft is obtained for transplantation or the patient's own liver regenerates sufficiently to resume normal function. It is thought that toxins contribute to the clinical picture of fulminant hepatic failure. The earliest reports of successful toxin removal were blood- and plasma-exchange transfusions. Given these successful case reports, mechanical liver-support devices were designed to filter toxins. These mechanical devices used hemodialysis, charcoal hemoperfusion, hemoperfusion through cation-exchange resins, hemodiabsorption, and combinations of all of these techniques as in the MARS liver-support device. Despite promising case reports and small series, no controlled studies of mechanical devices have ever showed a long-term survival benefit. Thus, the removal of presumed toxins seems to be insufficient to support patients with fulminant hepatic failure, and the biologic function of the liver must also be replaced. Attempts at replacing the biologic function have included extracorporeal liver perfusion, cross-circulation, and hepatocyte transplantation. Current technologies have combined mechanical and biologic support systems in hybrid liver-support devices. The mechanical component of these hybrid devices serves both to remove toxins and to create a barrier between the patient's serum and the biologic component of the liver-support device. The biologic component of these hybrid liver support devices may consist of liver slices, granulated liver, or hepatocytes from low-grade tumor cells or porcine hepatocytes. These biologic components are housed within bioreactors. Currently the most clinically studied bioreactors are those that use capillary hollow-fiber systems. Both the bioartificial liver by Demetrious and the extracorporeal liver-assist device by Sussman and Kelly are in clinical trials. Although the trials seemed to have yielded good survival data when the devices are used as a bridge to transplantation, the type and degree of liver support provided by these devices remains uncertain. Thus, despite decades of great progress in the field of artificial liver support, no one technique alone yet provides sufficient liver support. A hybrid system seems to be the best option at present. Still to be determined is the best tissue to use, how much liver tissue should be used, and the optimal design of the bioreactor.