Purpose: Bioartificial liver assist devices (BLADs) are expected to bridge liver failure patients to liver transplantation, but porcine endogenous retroviruses (PERVs) still pose a potential risk in pig-to-human xenotransplantation and thereby limit the use of bioartificial liver therapy. In our lab, fluidized-bed BLADs based on microencapsulated primary porcine hepatocytes have been successfully used to treat liver failure pigs. We detected the risk of PERVs transmission of microencapsulated primary porcine hepatocytes-the key component of fluidized-bed BLADs, to evaluate the biosafety of this device for further clinical applications.
Methods: Microencapsulated primary porcine hepatocytes (cell diameter = 300 μm) were cultured in Dulbecco's modified Eagles medium (DMEM). Microencapsulated cell culture supernatants were collected at 6, 12, 24 and 72 h. HEK-293 were cocultured with these supernatants, and the cocultured cells were harvested every 7 days. RT-PCR was used to detect PERVs transmission. RT-qPCR was used to get the number of virus copies. PK-15 was used as the positive control whereas HepG2 was used as the negative control.
Results: PERV was detected in all supernatants, and the viral load of the supernatants increased with time. Moreover, cocultured 293 cells were positive for PERV-specific sequences.
Conclusion: The kind of fluidized-bed BLADs based on microencapsulated primary porcine hepatocytes have risk of PERVs transmission. Further extensive pre-clinical study focused on biosafety is warranted.
Keywords: Bioartificial liver assist devices; Microencapsulated primary porcine hepatocytes; Porcine endogenous retroviruses; RT-PCR; RT-qPCR.