from the Johns
Hopkins Institute for Cell Engineering and the Kimmel Cancer Center have developed a new, nearly
100 percent efficient technique for turning blood cells into beating heart
Zambidis, M.D., Ph.D., study leader and assistant professor of oncology and
pediatrics at the Johns Hopkins Institute for Cell Engineering and the Kimmel
Cancer Center, along with Paul Burridge, Ph.D., a postdoctoral scientist at
Johns Hopkins, and a team of researchers, developed the method for creating
simple and virus-free beating heart cells.
studies used viruses to send genes into cells, which then turned them into stem
cells. The problem with this method is that viruses can mutate genes, which may
introduce cancer in new cells.
Zambidis and Burridge have developed a new method for
delivering genes to cells without the use of viruses. Instead, the new
technique involves the use of plasmids, which are rings of DNA that replicate
inside cells and then degrade over time. In addition, the new technique is
inexpensive, easy and almost 100 percent efficient.
able to do this by studying approximately 30 papers on other techniques that
create cardiac cells. They also drew charts of over 48 different variables that
play a role in creating cardiac cells, like enzymes, growth factors buffers and
timing. Making sure the stem cells are supplied with a mixture of growth
factors, nutrients and the right environmental conditions is a large part of
the process. This mixture can be different from laboratory to laboratory, and
now, after testing hundreds of different combinations of these variables,
Zambidis and Burridge have found four to nine vital recipes for each stage of
have recently optimized the conditions for complete removal of the fetal bovine
serum from one brief step of the procedure - it's made from an animal product
and could introduce unwanted viruses," said Zambidis.
then experimented with the new growth medium by coupling it with cord blood
stem cells and a plasmid that sends seven genes into the stem cells. An
electric pulse was sent to the cells as well, which created tiny holes in the
stem cells allowing the plasmids to enter. The plasmids then cause the cell to
slip into a "primitive" state, and can change into different cells.
These are called induced pluripotent stem cells (iPSC). From there, the iPSCs
were supplied with the new mixture, which is called the "universal cardiac
differentiation system." the cells were then placed in containers where
oxygen was reduced to a quarter of "ordinary atmospheric levels," and
a chemical called PVA was added to link the cells together. In a matter of nine
days, the iPSCs became tiny beating
to results, the mixture worked consistently for 11 different stem cell lines.
In each of the 11 cell lines, each plate of cells had around 94.5 percent
beating heart cells. It also worked for embryonic stem cells and adult blood
scientists get 10 percent efficiency for iPSC lines if they're lucky,"
addition to efficiency, another benefit was that the cost to make
the universal cardiac differentiation system was one-tenth cheaper than traditional
mixtures used for stem cells.
cardiac differentiation system took two years to make, and recently, the team
created similar methods for neural, vascular and retinal cells.
This study was
published in PLoS One.