Stem cells are often all over the media, and sometimes it seems like scientists take one step forward then three steps back within this field. We get excited, then it all goes quiet for a while. But recently some promising new developments have been made which could see a major progression in this field. But why is this particular research any different to anything that's been done before? Well, let's take a look.
Stem cells are like a blank slate; they haven't yet assumed a particular identity. But they have the potential to turn into a different type of specialised cell which can then go on to, for example, build a particular organ. There are two main types of stem cell; embryonic stem cells and adult stem cells. Since embryonic stem cells are obtained from early-stage embryos there are obviously important ethical considerations and many people disagree with using this type of cell. Therefore many people have focused on adult stem cells instead, which can be obtained from various places in the human body such as the bone marrow. But using bone marrow is extremely invasive, which understandably puts off donors. Scientists have been looking at alternatives, such as using easily obtainable blood samples to generate stem cells from.
When the scientists have obtained such adult cell samples, they need to transform them into a type of cell called human induced pluripotent stem cells (hiPSCs). These cells, like embryonic stem cells, have the ability to give rise to every cell type found in the body, such as brain cells, heart cells and kidney cells. But they have some advantages over embryonic stem cells, mainly because they are patient-matched; the risk for immune-rejection is therefore abolished. Previously, however, large quantities of blood have been required to do this.
hiPSCs have been successfully induced before; this isn't new. But what a group of researchers have shown in a paper published in Stem Cells Translational Medicine is that they can dramatically reduce the amount of patient blood required to do this. In fact, they have shown that a single finger-prick of blood is enough, and they induced the cells without the need for transgenes. Although the insertion of specific genes (transgenes) into the cells to induce pluripotency (the ability to turn into any other cell type) is generally the most efficient method, the risk of tumour development often outweigh the benefits. This group used a different method called cell reprogramming, and claim that to date this is the most efficient approach in the generation of hiPSCs from human blood samples.
But it doesn't stop there. Alongside proving that they could in fact use even less than a finger-prick's worth of blood, they hope to increase donors with a novel DIY blood-collection kit. This would allow individuals to collect their own samples and then send them off via courier, in a thermo box provided, to various stem cell banks which are currently being set up worldwide. This dramatically increases the number of donors that could be reached; those with mobility issues, perhaps because of physical disabilities or financial problems, and those in remote places. In particular, it could increase access to individuals with certain genotypes or diseases of interest. When the samples reach the banks they would be screened, induced, and then used in numerous applications such as disease modeling and drug screening.
The group, based at A*STAR's Institute of Molecular and Cell Biology, successfully demonstrated that the self-collected single drops of blood could be used not only for reprogramming, but blood typing and DNA sequencing also. They also managed to differentiate the reprogrammed cells into functional heart cells. The group hope that this could pave way for the development of a large-scale hiPSC bank, which has great potential for future therapeutic medicine.