Is endotoxin contamination of commercial growth factors a problem in stem cell research?
Significant development has been made in the field of stem cell (SC) research during the last decade. Expansion and differentiation of SC is highly dependent on growth factors (GF) supplemented to the cell culture system and the activity and purity of these GF is crucial for the readout of the studies as well as for future clinical applications. One of the main concerns with regards to purity is the contamination of bacterial endotoxins in the SC culture due to bacterially produced GF. Endotoxins, or lipopolysaccharides (LPS) in the outer membrane of gram-negative bacteria are difficult to eliminate completely in downstream purifications and it has been documented that concentration as low as 5 pg/ml can elicit unfavourable reactions in SC cultures. There is an immediate need to explore more thoroughly if currently acceptable levels of LPS contamination in commercial recombinant GF may affect SC behaviour and compromise their maintenance and differentiation. ORF Genetics has developed a technology to produce endotoxin-free GF in the grain of barley. ORF Genetics is currently coordinating a number of research projects addressing these important issues and first results indicate that only minute amount of endotoxin can be a real threat to SC culture systems.