Light-sensitive 3D retina created in
lab
Using
a type of human stem cell, researchers have now created a three-dimensional
(3D) functional human retinal tissue in the laboratory for the first time. ‘We
have basically created a miniature human retina in a dish that not only has the
architectural organisation of the retina but also has the ability to sense
light,’ claimed M. Valeria Canto-Soler, an assistant professor at John Hopkins
University’s school of medicine.
The
retinal tissue created in the laboratory – using human induced pluripotent stem
cells (iPS) – includes functioning photoreceptor cells capable of responding to
light, the first step in the process of converting it into visual images. ‘The
work advances opportunities for vision-saving research and may ultimately lead to
technologies that restore vision in people with retinal diseases,’ she noted.
Using a simple, straightforward technique they developed to foster the growth
of the retinal progenitors, the researchers saw retinal cells and then tissues
growing in petri dishes.
The
growth corresponded in timing and duration to retinal development in a human
foetus in the womb. Moreover, the photoreceptors were mature enough to develop
outer segments – a structure essential for photoreceptors to function. However,
Canto-Soler cautioned that photoreceptors are only part of the story in the
complex eye-brain process of vision, and her lab has not yet recreated all of
the functions of the human eye and its links to the visual cortex of the brain.
The achievement could eventually enable genetically engineered retinal cell
transplants that halt or even reverse a patient’s march toward blindness.
The findings appeared in the journal Nature
Communications.
Source: www.thehealthsite.com
12.06.2014
Coming soon – a single ‘magical’
injection to reduce risk of heart attack by upto 90 per cent?
Doctors
advise you to exercise, control your diet, reduce smoking and drinking and more
to reduce your cholesterol levels so that your risk for heart attack is
reduced. What if there was a magic potion that could be injected just once and
your heart attack risk would drop by a whopping 40-90 per cent?
Scientists
at Harvard Stem Cell Institute (HSCI) along with researchers at the University
of Pennsylvania have developed a ‘genome-editing’ approach for permanently
reducing cholesterol levels in mice through a single injection. ‘You have
people who have won the genetic lottery. They are protected from heart attack,
and there are no known adverse consequences. So that led us to reason that if
we could find a way to replicate this, we could significantly protect people
from heart attack,’ explained Kiran Musunuru from HSCI.
PCSK9
is a gene that works as cholesterol regulator. But some people have mutations
in PCSK9 that have the opposite effect. Those with the mutations have
low-density lipoprotein (LDL or bad) cholesterol levels about 15-28 percent
lower than the average level. And the people with that ‘good’ defect have heart
attack risks that range from about 47-88 percent below average. Musunuru and
his team project to turn normal PCSK9 genes into those with the ‘good’ defect.
The PCSK9 gene is expressed primarily in the liver.
It produces a protein that is active
in the bloodstream and prevents the removal of cholesterol from the blood. ‘The
main option for reducing cholesterol is statin drugs such as Lipitor but many
people taking statin drugs every day still have heart attacks. So there is
still a great need for other approaches,’ Musunuru noted. ‘With this genome-editing
technology, we can make permanent changes in the genome at the level of the
DNA,’ he added. The research was published in the journal Circulation
Research.
Source: www.thehealthsite.com
12.06.2014
Never choose a friend without complete
understanding and never lose a friend because of a small misunderstanding
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