Scientists have created artificial organs like liver, skin, intestine and windpipe that may revolutionize the way new medicines are being tested even as animal trials continue to face criticism.
Developed by Professor Heike Mertsching of the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart, in collaboration with Dr. Johanna Schanz, the test system should in future give pharmaceutical companies greater security and shorten the path to new drugs.
"Our artificial organ systems are aimed at offering an alternative to animal experiments. Particularly as humans and animals have different metabolisms. 30 per cent of all side effects come to light in clinical trials," said Mertsching.
"The special feature, in our liver model for example, is a functioning system of blood vessels. This creates a natural environment for cells," said Schanz.
Traditional models do not have this, and the cells become inactive.
"We don't build artificial blood vessels for this, but use existing ones - from a piece of pig's intestine," said Schanz.
They remove all of the pig cells, but preserve the blood vessels. Then the human cells are seeded onto hepatocytes, which are responsible for transforming and breaking down drugs, and endothelial cells, which act as a barrier between blood and tissue cells.
In order to simulate blood and circulation, the researchers put the model into a computer-controlled bioreactor with flexible tube pump, developed by the IGB.
Thus the nutrient solution is fed in and carried away in the same way as in veins and arteries in humans.
"The cells were active for up to three weeks. This time was sufficient to analyze and evaluate the functions. A longer period of activity is possible, however," said Schanz.
The researchers concluded that the cells work in a similar way to those in the body-they detoxify, break down drugs and build up proteins.
These are important pre-conditions for drug tests or transplants, as the effect of a substance can change when transformed or broken down.
Many drugs are only metabolised into their therapeutic active form in the liver, while others can develop poisonous substances.
The researchers have demonstrated the basic possibilities for use of the tissue models - liver, skin, intestine and windpipe.
Right now, the researchers are examining the test system, which could provide a safer alternative to animal experiments within two years.