Thanks to their new procedure, the ability to make new tissues from stem cells has taken a huge stride forward. Three years ago, a patient at Sahlgrenska University Hospital received a blood vessel transplant grown from her own stem cells. Suchitra Sumitran-Holgersson, Professor of Transplantation Biology at Sahlgrenska Academy, and Michael Olausson, Surgeon/Medical Director of the Transplant Center and Professor at Sahlgrenska Academy, came up with the idea, planned and carried out the procedure.
Now Sumitran-Holgersson and Olausson have published a new study in the journal EBioMedicine based on two other transplants that were performed in 2012 at Sahlgrenska University Hospital. The patients in this procedure were two young children who were afflicted with the same condition as in the first patient. All three patients were missing the vein that goes from the gastrointestinal tract to the liver.
“Once again we used the stem cells of the patients to grow a new blood vessel that would permit the two organs to collaborate properly,” Professor Olausson says. This time, however, Sumitran-Holgersson, found a way to extract stem cells that did not necessitate taking them from the bone marrow. “Drilling in the bone marrow is very painful,” she says. “It occurred to me that there must be a way to obtain the cells from the blood instead.”
The extreme youth of these patients motivated Sumitran-Holgersson find a new way to extract these stem cells. She came upon the extraction of stem cells from 25 millilitres (approximately 2 tablespoons) of blood, which is the minimum quantity of blood needed to obtain enough stem cells.
Then they used a novel technique to generate transplantable vascular grafts by using decellularized allogeneic vascular scaffolds that were then populated with peripheral whole blood and then grown in a bioreactor. Circulating, VEGFR-2 +/CD45 + and a smaller fraction of VEGFR-2 +/CD14 + cells largely repopulated the graft to form new vessels for transplantation.
Fortunately, her idea worked out better than she could have ever expected, and worked perfectly the first time. “Not only that, but the blood itself accelerated growth of the new vein,” Professor Sumitran-Holgersson says. “The entire process took only a week, as opposed to a month in the first case. The blood contains substances that naturally promote growth.”
Olausson and Sumitran-Holgersson have treated three patients so far, two children and one adult. Two of the three patients have recovered well and have veins that are functioning normally. In the third case the child is under medical surveillance and the outcome is less certain.
These studies show that it is feasible to avoid taking painful blood marrow samples to extract stem cells for blood vessel production, and that it is equally feasible to produce those blood vessels in a matter of a week.
“We believe that this technological progress can lead to dissemination of the method for the benefit of additional groups of patients, such as those with varicose veins or myocardial infarction, who need new blood vessels,” Professor Holgersson says. “Our dream is to be able to grow complete organs as a way of overcoming the current shortage from donors.”