Canadian scientists have transformed pinches of human skin into petri dishes of human blood — a major medical breakthrough that could yield new sources of blood for transfusions after cancer treatments or surgery.
The discovery, by researchers at McMaster University in Hamilton, Ont., could one day potentially allow anyone needing blood after multiple rounds of surgery or chemotherapy, or for blood disorders such as anemia, to have a backup supply of blood created from a tiny patch of their own skin — eliminating the risk of their body’s immune system rejecting blood from a donor.
Researchers predict the lab-grown blood could be ready for testing in humans within two years.
The start of human clinical trials would still mean a number of years before any widespread usage for treatment.
Human skin cells can be transformed into blood without first being sent through a primordial, stem-cell-like state, according to a ground-breaking study.
The breakthrough, published online today in Nature, follows work earlier this year showing that fibroblast cells from mouse skin, treated with the right cocktail of chemicals, can be transformed into neurons and heart muscle. However, it is the first study to accomplish this feat with human cells, and the first to create progenitor cells — in this case for blood.
“It takes us a step along the line to believing that you can produce anything from almost anything,” says Ian Wilmut, an embryologist and director of the MRC Centre for Regenerative Medicine in Edinburgh, UK. Such ‘direct conversions’ also offer a potentially safer, simpler tool for creating patient-specific cell therapies than is promised by adult cells reprogrammed to become stem cells (known as induced pluripotent stem cells, or iPS cells).
Mickie Bhatia, a stem-cell researcher at McMaster University in Hamilton, Canada, and his colleagues chose to make blood progenitors from skin cells because red blood cells created from stem cells do not make the adult form of haemoglobin. “Those cells, because they think they’re embryonic, make embryonic and fetal blood,” he says.
The achievement raises the possibility of personalizing blood production for patients for the first time.
The procedure is also relatively simple. It involves taking a small piece of skin just centimetres in size, which would require only a stitch to close, extracting fibroblasts — abundant cells in the skin that make up the connective tissue and give skin its flexibility — and bathing them in growth factors in a petri dish. Next, by adding a single protein that binds to DNA and acts as an on/off switch, the researchers turned on or off some 2,000 genes and reprogrammed the skin cells to differentiate or morph into millions of blood progenitors — the cells the produce blood.
They generated multiple different blood-cell types — oxygen-ferrying red blood cells, infection-fighting white blood cells, cells that make platelets needed for healing, and macrophages, the garbage trucks of the blood system that swallow and break down foreign material.
The work was repeated several times over two years using skin from adults, as well as neonatal foreskin, demonstrating, according to background material, that it could work “for any age of person.”
And while other researchers have reprogrammed fibroblasts into neurons, cardiac cells and even macrophage-like cells in mice, the McMaster team converted skin directly to blood using human skin.
The first to benefit could be patients with leukemia, whose blood undergoes genetic changes that turn it cancerous and who often need-bone marrow transplants, or those with lymphomas, such as Hodgkin’s disease.
Bone marrow contains stem cells that produce blood cells. If the bone marrow is coming from a donor, “first of all, you have to find a match, which can often be a problem, especially for smaller ethnic groups,” says Dr. Christine Williams, director of research at the Canadian Cancer Society Research Institute. There’s also a risk of rejection, where the body sees the matched cells as foreign.