Minimal nutritional requirements for growing and maintaining human embryonic stem cells

Researchers at Yale have established the minimal nutritional requirements for growing and maintaining human embryonic stem cells, a recipe that is critical for clinical application and for developmental studies, according to a report in the Proceedings of the National Academy of Sciences.

Human embryonic stem cells (hESCs) divide continuously over many generations and have the potential to differentiate into many different cell types. For hESCs to be useful in clinic, the nutrient mix they are grown in must be free of components that may contain toxins, viruses, or materials that might cause an immune response.

Led by Michael Snyder, professor of molecular, cellular and developmental biology, his team has documented a simple mix they call hESC cocktail, or HESCO, that contains only purified recombinant, chemically-synthesized, or purified human factors to support the cell growth.

The researchers based success of the recipe on how well the hESCs were able to preserve their growth characteristics and stem cell markers. To be successful, the cocktail also had to maintain normal cell chromosome profiles, or karyotypes, in the cells and fully support the ability of the cells to differentiate.

"Use of a minimal medium, that is sufficient for the embryonic stem cell growth is expected to make clinical application possible and facilitate developmental studies," according to Jean Lu, a post-doctoral associate and first author on the paper. "Cells incubated in HESCO are easy to grow in an undifferentiated state and can be readily induced to differentiate into all the three basic cell lineages."

The final cocktail for HESCO, that actively support hESC self-renewal, contains the growth factor Wnt3, basic fibroblast growth factor, insulin, transferrin, the B-cell activating factor April/BAFF, cholesterol, and albumin.