Page 24 - Hello Philippines December 2015 'B' ISSUE

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Health claims about vitamin D examined
“STEM cell researchers are
heralding a ‘major scientific discovery’,” Irwin Army Community Hospital,
BBC News reports.
Japanese scientists have created
pluripotent stem cells (stem cells
than can form all parts of the body)
essentially by dipping mouse blood
cells in acid, and then growing the cells
in the presence of specific chemicals. If
this could work in humans then it could
have a range of intriguing applications.
There are currently only four
established ways to obtain stem cells
which can form all parts of the body:
• from embryos
• from unfertilised eggs
• from embryo stem cells which
have undergone modification in the
laboratory
• from a mature cell such as a skin
cell, by reprogramming it with genes
using a virus in the laboratory
These current techniques are
lengthy and complex and using
embryonic stem cells also raises ethical
concerns.
This new technique may offer a
much quicker, simpler and less ethically
fraught method. The researchers found
that after exposing blood cells from
mice to a weak acid solution for 30
minutes, the cells were able to form
different types of cells (they became
pluripotent).
By growing these cells in the
presence of specific chemicals, the
researchers could also get the cells
to ‘self-renew’ (divide and renew
themselves for long periods). The
ability to self-renew and to form
different types of cells means that the
cells had become stem cells.
It is not known why exposure to
low pH should cause mature cells to
gain the ability to form different types
of cell under laboratory conditions.
And so far the research has only been
performed on cells from mice.
It should be noted that results were
not as good when blood cells were
taken from adult mice. This is exciting
research but it is likely to be some time
before the technique can be developed
for use in humans.
Where did the story come
from? The study was carried out by
researchers from the RIKEN centre for
Developmental biology, Kobe, Japan;
Tokyo Women’s Medical School;
HEALTH and Lifestyle
Harvard Medical School, Boston and
Kansas.
It was funded by the Intramural
RIKEN Research Budget, a Scientific
Research in Priority Areas, the Network
Project for Realization of Regenerative
Medicine, and the Department of
Anesthesiology, Perioperative and Pain
Medicine at Brigham and Women’s
Hospital.
The study was published in the
peer-reviewed medical journal Nature.
Generally the media reporting of
this study was accurate, although The
Times incorrectly assumed that any
weak acid would do – such as citric acid
(lemon juice).
The researchers used a specific acid
called “Hank’s balanced salt solution”
(which was described as having a
similar acidic (pH) level as Coca-
Cola) in addition to numerous other
chemicals under strict environmental
conditions in the laboratory.
What kind of research was this?
This was a laboratory study which
aimed to see if a mature cell (such as
a white blood cell, or lymphocyte)
could acquire the ability to produce
many different types of cell after being Mice made from a mixture of normal
exposed to a stress factor. Cells with
the ability to produce many different
types of cell are called “pluripotent”.
A similar process is known to occur in
plants after they are exposed to drastic
environmental changes.
As this was a laboratory study and
carried out in mice, it is not known
whether the findings would be directly
reproducible in humans.
What did the research involve?
The researchers took blood cells from
the spleens of week old mice. They
put them in a weak acid solution (pH
5.7) for 30 minutes at 37°C, and then
put them into petri dishes and grew
them at normal pH. The researchers
repeated this process with blood cells
from adult mice, and with cells from
different parts of the body of week old
mice (brain, skin, muscle, fat, bone
marrow, lung and liver tissues).
The researchers called the cells
they obtained from exposure to low
pH “stimulus-triggered acquisition of
pluripotency” or STAP cells.
The researchers did a number
of experiments to characterise the
STAP cells. They grew the cells in the
laboratory and observed whether they
had the ability to form different types
of cell, and injected them into mice to
see what would happen.
They injected STAP cells into mice
embryos and then implanted them
back into female mice. These cells were
labelled so that the researchers could
find out if they produced any cells in
the growing embryo.
What were the basic results? The
researchers found that after the low
pH treatment, blood cells lost features
characteristic of blood cells and gained physical damage, plasma membrane
features characteristic of pluripotent
cells.
These STAP cells could be obtained
from adult blood cells (but fewer
survived) and from other types of cell
(collected from the brain, skin, muscle, produced a type of stem cell from
fat, bone marrow, lung and liver
tissues).
The STAP cells could form many
types of tissue, both when grown in
the laboratory and when injected into
mice.
After being injected into early stage
embryos, it was found that STAP cells
could form all parts of baby mice,
and could make the whole embryo.
and STAP cells appeared to develop
normally, and the STAP cells were also
present in the offspring of these mice.
The researchers found that in
addition to being able to make all the
parts of the embryo, the STAP cells
could also form the placenta.
The ability to form all parts of
an embryo means that STAP cells
are similar to embryonic stem cells.
Embryonic stem cells make all cells
in the body and can self-renew, which
means that when they divide they form
another copy of themselves.
STAP cells were different to
embryonic stem cells in two key
respects: they could not divide that
many times, but they could form the
placenta (which could be useful),
whilst embryonic stem cells cannot.
The researchers carried out further
experiments and found that by
growing the cells in the presence of
different chemicals they could get the
STAP cells to self-renew, or in other
words become STAP stem-cells.
How did the researchers interpret
December 2015 / Fortnightly – No. 24 • UK & Europe Edition
the results? The researchers say, “This
study has revealed that somatic cells
latently possess a surprising plasticity. specific chemicals, and they are able to
This dynamic plasticity – the ability
to become pluripotent cells – emerges
when cells are transiently exposed
to strong stimuli that they would not
normally experience in their living
environments.”
They go on to say, “a remaining
question is whether cellular
reprogramming is initiated specifically
by the low-pH treatment or also by some
other types of sublethal stress such as
perforation, osmotic pressure shock,
growth-factor deprivation, heat shock
or high calcium exposure.”
Conclusion. This research has
shown a new, simpler technique
mature cells, though they have some
differences from embryonic pluripotent
stem cells.
The differences include that STAP
cells are not able to self-renew unless
they are grown in the presence of
form the placenta in addition to all the
different cell types making up the body.
The implication of both differences is
as yet unclear.
It is possible that in the future,
stem cells created using this technique
could be used to treat a wide range of
illnesses.
An example cited by BBC News is
age-related macular degeneration,
an eye condition caused by damage
to specialised cells inside the eyes.
The technique could potentially be
developed to generate cells to replace
the damaged cells.
A limitation of the research, so
far, seems to be the timing of when
the cells can be collected. The results
were best when blood cells were taken
from one week old mice, but not very
good when the samples were taken
from adult mice. Hopefully this can be
addressed through future research.
Longer studies will also need to be
completed to find out if the cells act
differently in the long run – for example,
producing too many or too few cells and
producing the right types of cells.
The researchers point out that
they do not yet have the answer as to
why the weak acid causes the cells to
change but they are continuing their
investigations.
Overall, this is an exciting piece of
research that may have long-lasting
implications on how stem cell research
and therapy is carried out in the future.
n NHS Choices