Reconstruction of liver organoid using a bioreactor.
OBJECTIVE
To develop the effective technology for reconstruction of a liver organ in vitro using a bio-artificial liver.


METHODS
We previously reported that a radial-flow bioreactor (RFB) could provide a three-dimensional high-density culture system. We presently reconstructed the liver organoid using a functional human hepatocellular carcinoma cell line (FLC-5) as hepatocytes together with mouse immortalized sinusoidal endothelial cell (SEC) line M1 and mouse immortalized hepatic stellate cell (HSC) line A7 as non parenchymal cells in the RFB. Two x 10(7) FLC-5 cells were incubated in the RFB. After 5 d, 2 x 10(7) A7 cells were added in a similar manner followed by another addition of 10(7) M1 cells 5 d later. After three days of perfusion, some cellulose beads with the adherent cells were harvested. The last incubation period included perfusion with 200 nmol/L swinholide A for 2 h and then the remaining cellulose beads along with adherent cells were harvested from the RFB. The cell morphology was observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). To assess hepatocyte function, we compared mRNA expression for urea cycle enzymes as well as albumin synthesis by FLC-5 in monolayer cultures compared to those of single-type cultures and cocultures in the RFB.


RESULTS
By transmission electron microscopy, FLC-5, M1, and A7 were arranged in relation to the perfusion side in a liver-like organization. Structures resembling bile canaliculi were seen between FCL-5 cells. Scanning electron microscopy demonstrated fenestrae on SEC surfaces. The number of vesiculo-vacuolar organelles (VVO) and fenestrae increased when we introduced the actin-binding agent swinholide-A in the RFB for 2h. With respect to liver function, urea was found in the medium, and expression of mRNAs encoding arginosuccinate synthetase and arginase increased when the three cell types were cocultured in the RFB. However, albumin synthesis decreased.


CONCLUSIONS
Co-culture in the RFB system can dramatically change the structure and function of all cell types, including the functional characteristics of hepatocytes. Our system proves effective for reconstruction of a liver organoid using a bio-artificial liver.
Saito
Masaya
M
Department of Laboratory Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan.
Matsuura
Tomokazu
T
Masaki
Takahiro
T
Maehashi
Haruka
H
Shimizu
Keiko
K
Hataba
Yoshiaki
Y
Iwahori
Tohru
T
Suzuki
Tetsuro
T
Braet
Filip
F
D000418:Albumins / Q000032:analysis; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001119:Arginase / Q000032:analysis; D001124:Argininosuccinate Synthase / Q000032:analysis; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D002460:Cell Line; D018920:Coculture Techniques; D022781:Hepatocytes / Q000166:cytology / Q000502:physiology; D006801:Humans; D019164:Liver, Artificial; D008387:Marine Toxins; D051379:Mice; D008863:Microspheres; D009940:Organoids / Q000033:anatomy & histology* / Q000502:physiology*; D012333:RNA, Messenger; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000418:Albumins; D000596:Amino Acids; D008387:Marine Toxins; D012333:RNA, Messenger; C086235:swinholide A; D001119:Arginase; D001124:Argininosuccinate Synthase