CREATING STEM CELLS FOR RESEARCH
How are stem cell therapies developed?
In What is the Goal of Stem Cell Research?, we explored ways that stem cells might be used to repair or replace damaged tissues, as well as some of the challenges researchers face when developing new therapies.
Stem cell therapies aren't invented overnight. Each potential therapy starts out as a testable idea based on initial research findings. That idea must be followed up with rigorous research and testing in the lab, which can take years - or even decades - of work. Even if the therapy looks great in lab experiments, it will become a viable treatment only after it is proven safe and effective in human clinical trials.
From ideas to therapies: where do we begin?
The first step is to establish an experimental model - a laboratory-based scenario that simulates the way a stem cell therapy might work in humans. To be useful, an experimental model must possess these features:
Researchers use two basic experimental models to develop stem cell therapies:
Here, we'll see how researchers create models for preliminary experiments: cell "lines" that grow in the laboratory. A stem cell line is a continuously dividing population of cells obtained from human or animal tissues. Researchers use both embryonic and adult stem cell lines as experimental models.
Embryonic stem cells
Embryonic stem cell lines are established from embryos shortly after fertilization. To create an embryonic stem cell line, an embryo must be separated into individual cells. A single cell from the embryo is placed in a dish and provided with nutrients and growth factors that stimulate it to divide. The resulting cell line will continue to divide as long as it is kept in a controlled environment and provided with appropriate growth factors to prevent differentiation.
Currently, most embryonic stem cell lines are created using mouse embryos. Researchers are currently evaluating several other sources for embryonic stem cells:
Adult stem cell lines
Adult stem cell lines isolated from mature tissues are another excellent resource for research studies. Most research is performed using adult stem cell lines from model organisms such as mice and rats, since obtaining adult stem cells from humans can involve invasive surgical procedures.
Supported by a Science Education Partnership
Award (SEPA) [No. 1 R25 RR16291-01] from the National Center for Research Resources, a component of the
National Institutes of Health, Department of Health and Human Services. The contents provided
here are solely the responsibility of the authors and do not necessarily represent the official
views of NCRR or NIH.