RESUMO
Alginate-encapsulated HepG2 cells cultured in microgravity have the potential to serve as the cellular component of a bioartificial liver. This study investigates their performance in normal and liver failure (LF) human plasma over 6-8 h in a fluidized bed bioreactor. After 8 days of microgravity culture, beads containing 1.5 x 10(9) cells were perfused for up to 8 h at 48 mL/min with 300 mL of plasma. After exposure to 90% LF plasma, vital dye staining showed maintained cell viability, while a 7% increase in lactate dehydrogenase activity indicated minimal cell damage. Glucose consumption, lactate production, and a 4.3-fold linear increase in alpha-fetoprotein levels were observed. Detoxificatory function was demonstrated by quantification of bilirubin conjugation, urea synthesis, and Cyp450 1A activity. These data show that in LF plasma, alginate-encapsulated HepG2 cells can maintain viability, and metabolic, synthetic, and detoxificatory activities, indicating that the system can be scaled-up to form the biological component of a bioartificial liver.
Assuntos
Alginatos/química , Reatores Biológicos , Células Hep G2/metabolismo , Falência Hepática/terapia , Fígado Artificial , Plasma/metabolismo , Albuminas/metabolismo , Amônia/metabolismo , Bilirrubina/metabolismo , Sobrevivência Celular , Terapia Baseada em Transplante de Células e Tecidos/métodos , Células Imobilizadas/citologia , Células Imobilizadas/metabolismo , Glucose/metabolismo , Ácido Glucurônico/química , Células Hep G2/citologia , Ácidos Hexurônicos/química , Humanos , L-Lactato Desidrogenase/metabolismo , Transaminases/metabolismoRESUMO
This study investigates the effect of rotary culture compared with static culture on the proliferation, cell viability, synthetic function and detoxificatory capacity of HepG2 cells encapsulated in 1% alginate. Cell viability and alginate bead morphology were maintained in the rotary culture system at day 10, while cell number showed a 4.5-fold increase compared with static culture. Protein production was increased in rotary cultures with a 4.1-fold increase in total albumin and a 4.4-fold increase in alpha1 antitrypsin levels in rotary compared with static culture at day 10. CYP4501A1/2 activity was maintained between the two culture systems. In conclusion, rotary culture increases proliferation rates leading to improved bead packing and a concomitant increase in total protein synthesis, along with maintenance of detoxificatory capacity. This allows a greater level of hepatic function to be expressed in a given volume, offering clear advantages for the design of liver support systems.
