The finding paves way for eliminating the need of radiation and chemotherapy in people with blood cancers such as leukaemia and blood disorders, such as sickle-cell disease
Scientists have produced vast quantities of blood stem cells in laboratory, using commonly available synthetic polymer that is soluble in water and found in glue.
For decades, researchers were looking for ways to grow blood-forming haematopoietic stem cells (HSCs) in large numbers in the lab. They tried using growth factors, but were unsuccessful because of impurities caused by albumin — a human blood protein. Albumin released by immune cells was stopping the cells from growing, according to a report in Nature, a science journal.
Thus, instead of albumin, stem-cell biologist Hiromitsu Nakauchi, who led the research teams from University of Tokyo in Japan and Stanford University in California, used polyvinyl alcohol (PVA) — the main ingredient found in glue.
To start producing blood cells, a cluster of mouse HSCs was expanded to almost 900 times its original level in just a month. These cells were then transplanted back into a different set of mice, where they thrived and developed into blood components, the report said.
“This has been my life goal,” Nakauchi, said in a statement.
The finding paves way for eliminating the need of radiation and chemotherapy in people with blood cancers such as leukaemia and blood disorders, such as sickle-cell disease, the report said.
Before most transplants, immune systems are eliminated or suppressed, without which it can destroy donor cells that are not a genetic match. But, the team found that the donor HSCs can be injected into mice without conditioning. When Nakauchi injected the cells into healthy mice with intact immune systems, the cells thrived. It could be because of the large numbers introduced, he said.
The idea of transplanting a mega-dose of HSCs is attractive, but requires further testing, first in mice and then in humans, Luigi Naldini, from the San Raffaele Hospital in Milan, Italy, was quoted in Nature report.
Nakauchi said the team is now working on the technique to grow human HSCs. But, some researchers warn that it is still unclear whether it will work with human cells. However, if successful, HSCs could be extracted from patients before reintroducing the cells into the patients and gene-editing tools can be used to correct any disease-causing mutations.
Calling the work as an "impressive data", George Daley, a stem-cell biologist at Harvard School of Medicine in Boston, Massachusetts, noted that this was the best evidence yet that lab-grown HSCs can survive for more than a few days and engraft when reinserted into the body.
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