title: Serum-free medium and mesenchymal stromal cells enhance functionality and stabilize integrity of rat hepatocyte spheroids.
abstract: Long-term culture of hepatocyte spheroids with high ammonia clearance is valuable for therapeutic applications, especially the bioartificial liver. However, the optimal conditions are not well studied. We hypothesized that liver urea cycle enzymes can be induced by high protein diet  and maintain on a higher expression level in rat hepatocyte spheroids by serum-free medium (SFM) culture and coculture with mesenchymal stromal cells (MSCs). Rats were feed normal protein diet (NPD) or high protein diet (HPD) for 7 days before liver digestion and isolation of hepatocytes.  Hepatocyte spheroids were formed and maintained in a rocked suspension culture with or without MSCs in SFM or 10% serum-containing medium (SCM). Spheroid viability, kinetics of spheroid formation, hepatic functions, gene expression, and biochemical activities of rat hepatocyte spheroids were  tested over 14 days of culture. We observed that urea cycle enzymes of hepatocyte spheroids can be induced by high protein diet. SFM and MSCs enhanced ammonia clearance and ureagenesis and stabilized integrity of hepatocyte spheroids compared to control conditions over 14 days. Hepatocytes  from high protein diet-fed rats formed spheroids and maintained a high level of ammonia detoxification for over 14 days in a novel SFM. Hepatic functionality and spheroid integrity were further stabilized by coculture of hepatocytes with MSCs in the spheroid microenvironment. These findings  have direct application to development of the spheroid reservoir bioartificial liver.
authors.affiliation: Department of Pathology, West China Hospital, Chengdu, Sichuan, People's Republic of China.
authors.forename: Ji
authors.initials: J
authors.lastname: Bao
authors.forename: James E
authors.initials: JE
authors.lastname: Fisher
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Lillegard
authors.forename: William
authors.initials: W
authors.lastname: Wang
authors.forename: Bruce
authors.initials: B
authors.lastname: Amiot
authors.forename: Yue
authors.initials: Y
authors.lastname: Yu
authors.forename: Allan B
authors.initials: AB
authors.lastname: Dietz
authors.forename: Yaakov
authors.initials: Y
authors.lastname: Nahmias
authors.forename: Scott L
authors.initials: SL
authors.lastname: Nyberg
mesh_terms: D000818:Animals; D016895:Culture Media, Serum-Free; D004195:Disease Models, Animal; D022781:Hepatocytes / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism; D019164:Liver, Artificial; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018874:Spheroids, Cellular
chemical_list: D016895:Culture Media, Serum-Free