Replacing animal-derived enzymes and cells for in vitro research

Enzymes are widely used across the life sciences both directly in research to understand metabolism and indirectly to facilitate experimentation. Many enzymes are refined from animal sources, presenting the risk of potential contamination with viruses or prions as well as animal welfare concerns. For example, trypsin is a proteolytic enzyme widely used in routine cell culture for the dissociation of adherent cells, isolated from porcine pancreas as a by-product of the food industry.

Other metabolic components used as part of in vitro research can introduce variation between experiments or laboratories. For example, the S9 fraction derived from rat liver is commonly used to study drug metabolism, however, its complete composition is not known and there are significant differences in liver metabolism between rodents and humans [1]. These differences reduce the reliability of metabolism data extrapolated from animal models to humans. To begin addressing these concerns, we are supporting the development of assays that remove animal-derived reagents such as the S9 fraction through the Animal-free in vitro Challenge.

Enzymes from animal-free sources are increasingly available, whether as recombinant enzymes or derivatives from plants or bacteria. Animal-free enzymes generally have minimal variability and lower risk of contamination [2]. Listed below are companies that offer a selection of animal-free enzymes for a variety of applications.

Companies offering animal-free recombinant enzymes:

• BioVision
• Innovative Research
• Merck
• Worthington Biochemical Corporation

Companies offering alternatives to trypsin for cell culture:

• Applied Biotechnology Institute
• Biological Industries
• Cellseco
• Genlantis
• Lonza
• Merck
• Sartorius
• ThermoFisher

The Swiss Institute of Bioinformatics hosts The Cellosaurus, a knowledge resource on cell lines which aims to describe all cell lines used in biomedical research [1]. It is a useful tool for users seeking to replace cell lines of animal-origin with those from human tissue, or to develop new assays with human cells. The use of human cells in in vitro models increases the relevance of experimental data, leading to improved translation of preclinical experiments. (Please note that the database also describes cell lines of animal-origin.)