Stem cell technology makes it possible to grow human neurons in the lab using skin or blood cells from donors. This allows us to compare lab-grown neurons, from patients with a particular disorder such as Alzheimer’s or epilepsy, with cells from healthy donors. Earlier studies had shown that there is considerable variation between stem cells from different donors. It was unclear, however, how many donors and neurons per donor were needed for reliable stem cell research. That prompted the scientists to develop a web tool for calculating the optimal study design. The study was led by Matthijs Verhage and Sophie van der Sluis from the Center for Neurogenomics and Cognitive Research (CNCR) and is published in the journal Molecular Psychiatry.
Optimal study design
To determine the optimal study design, the scientists made stem cells from donated skin cells and blood cells and then used them as a basis for growing human neurons. The neurons were subjected to a range of commonly used experimental techniques to get a clear picture of the variation in growth, composition and function between lab-grown neurons from different people. Based on the measured variation, they then used computer simulations to calculate how many donors and neurons are needed to obtain robust and reliable study results.
“When we compared these numbers with those in previously published studies, we saw that the majority did not use enough donors to comply with the statistical guidelines. Those studies might consequently have missed differences between the study groups, or may even have measured differences that are not caused by the disease, but rather by differences between individuals,” says Jessie Brunner, one of the three first authors of the article.
The medical world has pinned its hopes on stem cell technology in the battle against a range of diseases. The scientists argue that stem cell research needs to be conducted in a thorough, robust and replicable manner if this hope is to be realised. They therefore developed a web tool based on their calculations that stem cell researchers around the world can use to optimise their study designs. “This enables researchers to determine the most informative study design for their specific research question and how much data they need to collect to reach reliable conclusions,” says Brunner.
Larger and smarter
The scientists conclude that if stem cell research is to make a real contribution to science and medical progress, study designs require larger cohort sizes and need to be smarter than at present. Where studies are conducted without the requisite care and diligence, because the work is time-consuming and the necessary stem cells are difficult to obtain, for example, there is a significant likelihood of unreliable or even inaccurate findings. Brunner: “Robust and reliable study results are essential for gaining a better understanding of brain disorders and developing new therapies. That is a key driver in our work. The web tool contributes not just to robust and reliable study results, but also helps to ensure optimal work efficiency. That is important given that working with stem cells is labour-intensive, expensive and complex.”