Stem cells can be donated by adults, but they can also be collected immediately after birth from the umbilical cord. To keep the risk of rejection to a minimum, the immune system of both the donor and the recipient are compared. For the majority of Dutch patients, there are several stem cell donors suitable. 'We select the best, and by the best we mean the donor cells with the least possible risk of rejection,' explains Belderbos.
'We currently do not pay particular attention to the age of the donor,' says Belderbos. 'But if you transplant stem cells in children, then of course the donor cells are meant to last them a lifetime.' Aging changes the DNA. Every time a cell splits, the DNA is copied and errors can occur during the process. The older a person is, the more their cells have divided and the more errors may have occurred. Consequently, diseases like cancer, which are driven by errors in the DNA, occur more frequently at an advanced age by which time the cells have already split numerous times. Donor stem cells have split numerous times as well – those of an adult more often than those collected from an umbilical cord.
'It is only relatively recently that we have been able to transplant stem cells,' says Belderbos. 'The longest living stem cell recipient underwent stem cell treatment 40 years ago. We do not yet have a good understanding of the impact of cellular aging on stem cell treatment.' In order to discover the significance of the age of cells, Belderbos grows stem cells in the lab to measure the errors in their DNA. She also compares the number of DNA errors in the stem cells of the donor and of the recipient in order to analyze the effect of transplant treatment. 'We need to know how much importance we should attach to the age of the cells, especially when transplanting stem cells in children,' says Belderbos. 'So I am delighted with this award. It gives my research more clout.'
In this video, Mirjam Belderbos elaborates on her project.