Their experiments first confirmed that serum interferes with the metabolism of cultured rat and human liver cells. They then found that liver cells grown with endothelial cells in a serum-free culture with 95 percent oxygen quickly resume normal metabolic activity, including gene expression and cell function. These cultured cells successfully predicted the clearance rates for both rapid- and slow-acting drugs and maintained a high level of metabolic activity for several weeks.

"This is a significant achievement," says Martin Yarmush, MD, PhD, director of the MGH Center for Engineering in Medicine and a co-author of the PNAS study. "Oxygen had been thought to affect cell survival but not gene expression or the function of cultured liver cells. This all changed when we started looking at new formations of culture media." Yarmush is the Helen Andrus Benedict Professor of Surgery at Harvard Medical School, where Nahmias is an instructor in Bioengineering.

The new culture system is being licensed to H REL Corporation of Beverly Hills, Calif., a company developing human-relevant models of drug metabolism. Future work will explore extending these results to other cell systems and clinical applications, such as transplantation of liver cells.

Source: Massachusetts General Hospital