In a recent breakthrough, scientists have discovered how to grow copious amounts of adult stem cells, potentially ensuring that everyone who needs a bone marrow transplant receives one.
Researchers at Ansary Stem Cell Institute have discovered that endothelial cells – basic building blocks of the vascular system – can be co-cultured with stem cells to produce an unlimited supply of blood-related stem cells.
“This is groundbreaking research with potential application for regeneration of organs and inhibition of cancer cell growth,” said Dr Antonio M Grotto Jr. The study shows that blood vessels are not just passive channels for delivery of oxygen and nutrients but are programmed to maintain and produce stem cells and their mature forms in adult organs.
Researchers used endothelial cells to encourage growth of stem cells without added growth factors and serum. They chose endothelial cells because of their close contact with blood cells and previous work demonstrated they produced novel stem-cell-active growth factors. The cells were genetically engineered to stay in a long term survival state by inserting a gene cloned from adenovirus.
“This study will have a major impact on the treatment of any blood-related disorder that requires a stem cell transplant,” said Dr Shahin Rafii, the study’s senior author, “Most stem cells, even in the presence of multiple growth factors, serum and support from genetic non-endothelial stromal cells, die within a few days. Now, employing our endothelial stem cell co-cultures, we can propagate bona fide adult stem cells in the absence of external factors and serum beyond 21 days.”
Physicians could use this strategy to propagate any source of hematopoietic stem cells exponentially, banking them for transplantation into patients. The model could be used to grow stem cells for other organs like the brain, heart, skin and lungs.
The research showed that endothelial cells can instruct stem cells to generate mature differentiated progeny that could form immune cells, platelets and red and white blood cells, suggesting that endothelial cells promote stem cell reconstitution.
Researchers worried that forced expansion of the stem cells could lead to cancerous mutations, but there was no indication of tumour formation even after a year after re-transplantation into laboratory mice.
Dr Rafii said: “We will be able to selectively activate endothelial cells not only to induce organ regeneration but also to inhibit specifically the production of endothelial cell-derived factors in order to block the growth of tumours.”