A new system for growing human embryonic stem cells could make therapies utilising the cells safer for patients, concludes a study published online by The Lancet (Tuesday, March 8, 2005).
Human embryonic stem cells have the potential to treat a wide range of serious and often life-threatening conditions. Once isolated from the embryo, stem cells are usually cultured in animal derived material called feeder layers. However, exposing stem cells to live animal cells presents a risk of contamination with retroviruses and other pathogens that could be transmitted to the patient.
Robert Lanza and colleagues (Advanced Cell Technology, MA, USA) used a sterile protein matrix to generate and culture embryonic stem cells. A new stem cell line was derived from human embryos under completely cell and serum free conditions. After more than 6 months of unspecialised growth the cells retained the potential to form particular tissues.
Dr Lanza comments: “Experience with organ and tissue transplantation has shown that disease such as HIV infection and Creutzfeldt-Jakob disease, hepatitis B or C viruses, and other infectious agents can be transmitted from human donor cells to the recipient. Similarity, co-culture of human embryos with live animal cells causes concern for infection with recognised or as yet unrecognised infectious agents. We derived and established new human embryonic stem-cell lines in completely feeder-layer free conditions. Our findings help solve one of the major problems associated with the use of human embryonic stem-cell therapy in the treatment of human medical conditions.”
In an accompanying comment Dr Outi Hovatta (Huddinge University Hospital, Sweden) states: “According to new EU directive human embryonic stem cells for transplantation have to be cultured in conditions of Good Manufacturing Practice to guarantee the safety and quality of cells. Identifying all culture constituents meeting Good Manufacturing Practice is now an important challenge for those who derive human-embryonic stem-cell line. There are other challenges: how to avoid immune reactions in transplantation, and how to prevent genetic changes during long-term culture. And before clinical treatment, the controlled differentiation of the cells still requires research.”