Microbiological safety of a novel bio-artificial liver support system based on porcine hepatocytes: a experimental study

Abstract

BackgroundOur institute has developed a novel bio-artificial liver (BAL) support system, based on a multi-layer radial-flow bioreactor carrying porcine hepatocytes and mesenchymal stem cells. It has been shown that porcine hepatocytes are capable of carrying infectious porcine endogenous retroviruses (PERVs) into human cells, thus the microbiological safety of any such system must be confirmed before clinical trials can be performed. In this study, we focused on assessing the status of PERV infection in beagles treated with the novel BAL.MethodsFive normal beagles were treated with the novel BAL for 6 hours. The study was conducted for 6 months, during which plasma was collected from the BAL and whole blood from the beagles at regular intervals. DNA and RNA in both the collected peripheral blood mononuclear cells (PBMCs) and plasma samples were extracted for conventional PCR and reverse transcriptase (RT)-PCR with PERV-specific primers and the porcine-specific primer Sus scrofa cytochrome B. Meanwhile, the RT activity and the in vitro infectivity of the plasma were measured.ResultsPositive PERV RNA and RT activity were detected only in the plasma samples taken from the third circuit of the BAL system. All other samples including PBMCs and other plasma samples were negative for PERV RNA, PERV DNA, and RT activity. In the in vitro infection experiment, no infection was found in HEK293 cells treated with plasma.ConclusionsNo infective PERV was detected in the experimental animals, thus the novel BAL had a reliable microbiological safety profile.

Improved survival of porcine acute liver failure by a bioartificial liver device implanted with induced human functional hepatocytes

“…Among different batches of hiHep preparation, hepatic genes were expressed at comparable levels and consistent numbers of cells were harvested, indicating that the expansion procedure was robust and reproducible ( Supplementary information, Figure S4A and S4B ). hiHeps thus produced were applied in a homemade BAL support system 19 , 20 , 21 , 22 , 23 .…”

“…The homemade BAL support system consisted of a multi-layer radial-flow bioreactor, a plasma filter separating blood cells and blood plasma, a plasma component exchanger serving as immunoprotective barrier, and other accessories 19 , 20 , 21 , 22 , 23 ( Figure 2A ). The fully assembled bioreactor contained a stack of 65-layer round flat plates, which were made of polycarbonate ( Supplementary information, Figure S5A ).…”

Performance of cold-preserved rat liver Microorgans as the biological component of a simplified prototype model of bioartificial liver

“…Investigations concerning the development of BAL devices containing normal hepatocytes are still being conducted[3,4]. Some researchers have chosen to employ immortalized hepatocytes[5] while others have focused their efforts in preparing bioreactors housing isolated hepatocyte with or without extra-cellular matrix and structural components[6,7].…”

Establishment of gene‐edited pigs expressing human blood‐coagulation factor VII and albumin for bioartificial liver use

“…On the contrary, porcine primary hepatocytes are abundant and close to human hepatocytes in terms of metabolism and detoxication activity. Moreover, porcine primary hepatocytes are the earliest and the most widely used cell source for clinical trials of BALs for they are easily accessible …”

“…Moreover, porcine primary hepatocytes are the earliest and the most widely used cell source for clinical trials of BALs for they are easily accessible. [5][6][7][8][9][10] Two main concerns for porcine primary hepatocytes to become an ideal cell source of BALs for clinical application are their immunogenicity and risk of transmitting porcine endogenous retrovirus (PERVs). Although there is no report of PERVs transmission from pig to human in clinical trials to date, [11][12][13][14] it is already known that PERVs can infect human cells in vitro, 15,16 and retroviral vector pseudotypes bearing PERV-A and PERV-C (PERV-A/C recombinants) have a much higher chance to infect humans.…”