Transplantable human blood stem cells created in lab

Clinically usable, laboratory-developed blood stem cells have been produced using a novel method.

Researchers in Australia report that their blood stem cells 'closely resemble' those that naturally develop in the human body. Publishing their findings in Nature Biotechnology, the group developed a method which reprogrammes patient cells into stem cells and then turns them into blood stem cells, which are needed for bone marrow transplantation.

'Prior to this study, developing human blood stem cells in the lab that were capable of being transplanted into an animal model of bone marrow failure to make healthy blood cells had not been achievable. We have developed a workflow that has created transplantable blood stem cells that closely mirror those in the human embryo,' the lead researcher, Dr Elizabeth Ng from the Murdoch Children's Research Institute (MCRI) in Melbourne, Australia, said. 'Importantly, these human cells can be created at the scale and purity required for clinical use.'

The technology uses four reprogramming factors to transform blood or skin cells into pluripotent stem cells. These factors return the cells to an earlier stage of development, where they are capable of becoming any cell type in the body.

In this study, the stem cells were transplanted into the bone marrow of laboratory mice with weakened immune systems, simulating the condition of blood cancer patients. Researchers found that the cells integrated well into the bone marrow and were able to produce all types of blood cells, similar to how umbilical cord blood cell transplants function.

Patients with blood cancer such as leukaemia are typically treated with radiotherapy. This process destroys the natural environment of blood stem cells in the bone marrow, which is why patients require blood stem cell transplants, such as those from umbilical cord blood. However, even when the donor's blood type matches the patient's, the transplant can be rejected by the body and cause illness or, in severe cases, death.

Commenting on the feasibility of patient-derived blood stem cell transplants, Professor Andrew Elefanty, co-lead researcher and group leader of the Blood Diseases Laboratory at MCRI, added: 'Developing personalised, patient-specific blood stem cells will prevent these complications, address donor shortages and, alongside genome editing, help correct underlying causes of blood diseases.'

The next stage of patient-derived blood stem cell transplants will involve testing their safety in humans. According to Professor Elefanty, with the support of government grants, Phase I clinical trials could begin in about five years.