By using different new drug combinations, scientists at Imperial College London have tricked bone marrow into releasing specific kinds of adult stem cells into the bloodstream-a technique that in future could be used to repair heart damage or mend a broken bone.
At the time of disease or an injury, a person's bone marrow mobilises different types of stem cells to help repair and regenerate tissue.
Thus, the researchers showed that it may be possible to boost the body's ability to repair itself and speed up repair by using different new drug combinations to put the bone marrow into a state of 'red alert' and send specific kinds of stem cells into action.
In the new study, the bone marrow of healthy mice was tricked into releasing two types of adult stem cells - mesenchymal stem cells.
Such cells could turn into bone and cartilage and can also suppress the immune system, and endothelial progenitor cells, which can make blood vessels and therefore have the potential to repair damage in the heart.
They treated healthy mice with one of two different 'growth factors' - proteins that occur naturally in the bone marrow - called VEGF and G-CSF, after which, the mice were given a new drug called Mozobil.
The study is the first to selectively mobilise mesenchymal stem cells and endothelial progenitor cells from the bone marrow.
This technique is already used in bone marrow transplants in order to boost the numbers of haematopoietic stem cells in a donor's bloodstream.
In the study, the researchers could choose which groups of stem cells the bone marrow released, by using two different therapies.
In the end, the researchers hope to use the new technique to repair and regenerate tissue, for example when a person has heart disease or a sports injury, by mobilising the necessary stem cells.
The researchers also hope that they could tackle autoimmune diseases such as rheumatoid arthritis, where the body is attacked by its own immune system, by kicking the mesenchymal stem cells into action. The stem cells are able to suppress the immune system.
"The body repairs itself all the time. We know that the skin heals over when we cut ourselves and, similarly, inside the body there are stem cells patrolling around and carrying out repair where it's needed. However, when the damage is severe, there are limits to what the body can do of its own accord," said Dr Sara Rankin, the corresponding author of the study from the National Heart and Lung Institute at Imperial College London.
She added: "We hope that by releasing extra stem cells, as we were able to do in mice in our new study, we could potentially call up extra numbers of whichever stem cells the body needs, in order to boost its ability to mend itself and accelerate the repair process.
Further down the line, our work could lead to new treatments to fight various diseases and injuries which work by mobilising a person's own stem cells from within."
Now, the scientists are hoping to investigate whether releasing repair stem cells into the blood really does accelerate the rate and degree of tissue regeneration in mice that have had a heart attack.
On the basis of the results of the study, the scientists hope to conduct clinical trials of the new drug combinations in humans within the next ten years.
The researchers are also keen to explore whether ageing or having a disease affects the bone marrow's ability to produce different kinds of adult stem cells.
They want to investigate if the new technique might help to reinvigorate the body's repair mechanisms in older people, to help them fight disease and injury.
The study was published in the journal Cell Stem Cell.