Hepatic co-cultures

Our hepatic co-cultures are powerful new in vitro tools for modeling the liver. Hepatocyte monocultures have served as the standard in vitro model for ADME/Tox-related research, including metabolism and drug-drug interactions.  However, a growing body of evidence demonstrates that monocultures of hepatocytes alone are not predictive of certain physiological conditions.

Growing evidence shows that under both normal and pathological conditions, many hepatocyte functions are regulated by substances released from neighboring non-parenchymal cells (NPC). These cells, particularly Kupffer cells, play an important role in the modulation of xenobiotic metabolism in the liver.  Studies indicate that co-culture of hepatocytes with NPCs would better represent both normal liver physiology as well as disease states.

Figure 1: Model normal and inflamed liver states. These models enable researchers to study the interactions between hepatocytes and Kupffer cells during liver inflammation.

• Kupffer cells play an active role in the remodeling and maintenance of liver extracellular matrix.
• Kupffer cells secrete potent mediators of the inflammatory response that control liver inflammation.
• Kupffer cell cytokine mediators control hepatocyte metabolic rates through direct interactions with phase I and phase II enzymes.

Kupffer cell and hepatocyte co-cultures can self-assemble within 72 hours of treatment with pro-inflammatory cytokines or LPS, and can function by effectively modulating P450 expression in co-cultured hepatocytes. IL6 is significantly up-regulated in co-cultures at 72 hours as compared with Kupffer cells alone. This suggests functionality and self assembly between Kupffers and hepatocytes (Figures 2 and 3). This functionality is further demonstrated in the Rat co-cultures by the modulation of CYP3A and CYP1A2 activities (Figure 4).

Figure 2 (Above) — IL6 production in Kupffer cells after LPS and IL2 stimulation for 24, 48 and 72 hrs. As expected, following activation with LPS treatment, IL6 production is significantly up-regulated at 24 hrs and then progressively decreases, suggesting desensitization of Kupffer cells to chronic stimulation with LPS.

 

Figure 3 (Above) — IL6 production in Kupffer cells and hepatocyte co-cultures after LPS and IL2 stimulation for 24, 48 and 72 hrs. Note that IL6 is significantly up-regulated in co-cultures at all time points of 24, 48 and 72 hrs. This suggests cellular self assembly between Kupffer cells and hepatocytes that synergistically allows those cells to function together during resolution of inflammation.

Figure 4 (Below) — Modulation of CYP3A23 and CYP1A2 enzyme activities in co-cultures after LPS and IL2 stimulation for 72 hrs.  Note near 80% decrease of CYP3A23 and CYP1A2 after IL2 treatment.