LONDON, July 22 (UPI) -- British scientist say embryonic stem cells turned into photoreceptors can integrate into a live retina, possibly promising new treatments for eye diseases.

Writing in the journal Nature Biotechnology, researchers from University College London report producing rod-like photoreceptors from embryonic stem cells and successfully transplanting them into the retinas of mice.

The result suggests embryonic stem cells may one day lead to treatment for eye diseases sush retinitis pigmentosa, macular degeneration or other degenerative conditions that can cause loss of vision.

The researchers say they've developed a new method for growing embryonic stem cells that allows them to become immature eye cells and self-organize into three-dimensional structures similar to those seen in a developing retina.

In laboratory tests, the structures were transplanted into the retinas of night-blind mice where they integrated with the natural cells of the eye and formed synaptic connections, the MIT Technology Review reported Monday.

While the technique is probably years away from human trials, embryonic stem cells are already being tested in clinical trials in Japan for macular degeneration.

Researchers there say an alternative source of stem cells, dubbed induced pluripotent stem cells, will soon move into human trials as a treatment for eye disease.

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Stem cells turned into photoreceptors could treat vision loss

23 July 2013

Magnets could be a tool for directing stem cells to treat conditions such as heart or vascular disease.

By feeding stem cells particles made of magnetised iron oxide, scientists at Emory University and the Georgia Institute of Technology believe they can then use magnets to attract the cells to a particular location in the body after intravenous injection.

The results are published online in the journal Small and will appear in an upcoming issue. The paper was a result of collaboration between the laboratories of W. Robert Taylor of Emory, and Gang Bao of Georgia Tech. Taylor is professor of medicine and biomedical engineering and Bao is professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University.

The study used mesenchymal stem cells that can be obtained from adult tissues such as bone marrow or fat and are capable of becoming bone, fat and cartilage cells, but not other types of cell such as muscle or brain. They secrete a variety of nourishing and anti-inflammatory factors, which could make them valuable tools for treating conditions such as cardiovascular disease or autoimmune disorders.

Magnetized iron oxide nanoparticles are already US Food and Drug Administration (FDA) approved for diagnostic purposes with magnetic resonance imaging (MRI). Other scientists have tried to load stem cells with similar particles, but found that the coating on the particles was toxic or changed the cells properties.

The nanoparticles used in this study have a polyethylene glycol coating that protects the cell from damage. Another feature is that the Emory/Georgia Tech team used a magnetic field to push the particles into the cells, rather than chemical agents used previously.

We were able to load the cells with a lot of these nanoparticles and we showed clearly that the cells were not harmed, Taylor said in a statement. The coating is unique and thus there was no change in viability and perhaps even more importantly, we didnt see any change in the characteristics of the stem cells, such as their capacity to differentiate. This was essentially a proof of principle experiment. Ultimately, we would target these to a particular limb, an abnormal blood vessel or even the heart.

The particles are coated with the non-toxic polymer polyethylene glycol, and have an iron oxide core that is about 15 nanometres across. For comparison, a DNA molecule is two nanometres wide and a single influenza virus is at least 100 nanometres wide.

The particles appear to become stuck in cells lysosomes, which are parts of the cell that break down waste. The particles stay in one place for at least a week and leakage cannot be detected. The scientists measured the iron content in the cells once they were loaded up and determined that each cell absorbed roughly 1.5 million particles.

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Magnetised carriers help steer stem cells to therapy sites

Scientists in Britain have taken a significant step towards the possibility of reversing certain forms of blindness using stem cells.

For the first time, researchers have successfully grown light sensitive mouse retina cells from embryonic stem cells in the lab and transplanted them into night-blind mice.

Following the transplantation, the cells appeared to develop normally, by integrating into the existing retina and forming nerve connections needed to transmit visual information to the brain.

The findings are published in the latest edition of Nature Biotechnology.

It is not yet clear how the technique would work in humans.

There are two types of photoreceptors in the eyes, known as rods and cones.

Rods are important for night vision.

Using a new technique involving 3D culture and differentiation of mouse stem cells recently developed in Japan, the team grew retinas containing all the different nerve cells needed for sight.

They then transplanted 200,000 of the artificially grown photoreceptor cells into retina of the night blind mice.

Three weeks later a much smaller number of the cells had integrated into the mouse retina and had begun looking like normal mature rod cells.

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Stem cells could help reverse some blindness

July 22, 2013

A new study published in the journal Nature Biotechnology represents a major step forward in curing certain types of blindness.

Described to the BBC News as a significant breakthrough, the UK-based study outlined a groundbreaking technique developed by doctors at Moorfields Eye Hospital and University College London that uses stem cell therapy to replace photoreceptors that may have died as a result of Stargardts disease or age-related macular degeneration.

While previous efforts have successfully focused on keeping the photoreceptors support cells alive, the new treatment aims to replace the retinas key cells directly. These cells sense light and are connected to other cells that relay the visual information to the brain.

The new technique expands on work done by Japanese researchers who used mice stem cells to fashion new retinas. The London team created photoreceptor cells and placed them in the eyes of blind mice.

After being injected, the new cells were able to connect with the mices existing framework albeit at a relatively low level of effectiveness. Approximately 1,000 of the 200,000 transplanted cells were able to connect with the rest of the eye.

This is a real proof of concept that photoreceptors can be transplanted from an embryonic stem cells source and it give us a route map to now do this in humans, said lead researcher Robin Ali, a professor of Human Molecular Genetics at the University College of London. Thats why were so excited, five years is now a realistic aim for starting a clinical trial.

The eye is one of the most promising candidates for stem cell therapy because there is only one type of intermediary cell between photoreceptors and the brain, unlike other organs which require far more connections between newly generated cells. A relatively small number tens of thousands of stem cells could improve vision, a number that would not make much of a difference in the liver or brain.

The eyes relatively weak local immune system also makes it an ideal candidate for stem cell therapy. A weak immune system means a lower chance of transplanted cells being rejected.

While experts described the study as a huge leap forward, some expressed concerns about the stem cells relatively low connection rate.

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Using Stem Cells To Treat Blindness

Scientists turn embryonic stem cells into photoreceptors that can integrate into a live retina.

Transplanted photoreceptors derived from embryonic stem cells (green) integrate into the damaged retina of an adult mouse and touch the next neuron in the retinal circuit (red).

Scientists in the U.K. have produced rod-like photoreceptors from embryonic stem cells, and successfully transplanted them into the retinas of mice. The work suggests that embryonic stem cells could perhaps one day be used as a treatment for patients who have lost their vision to retinitis pigmentosa, macular degeneration, or other degenerative conditions in which the light-detecting rods and cones of the retina die over time.

Currently, there are few treatment options for these conditions; electronic implanted devices are available for some patients in some countries, but their efficacy is limited (see A Second Artificial Retina Option for the E.U. and What Its Like to See Again with an Artificial Retina).The new work,reported in Nature Biotechnology on Sunday, offers hope for a more effective, comprehensive treatment.

The researchers used a new method for growing embryonic stem cells that enables them to turn into immature eye cells and self-organize into three-dimensional structures similar to those seen in a developing retina (see Growing Eyeballs). Immature light-detecting cells were harvested from this culture and transplanted into the retinas of night-blind mice. There, the cells integrated with the natural cells of the eye and formed synaptic connections. The work did not involve testing how well the mice could see after the cells were implanted.

While this particular technique is probably years away from human trials, embryonic stem cells are already being tested in clinical trials for macular degeneration and Stargardts macular dystrophy. Last week, in fact, Japanese authorities announced that an alternative source of stem cells will soon move into human trials as a treatment for eye disease.The BBC reported that Japan has approved the first clinical trial of induced pluripotent stem cells, or iPS cells. These stem cells are made by reprogramming normal adult cells so that they return to a more embryonic-like state so that they can then be converted into other cell types, such as retinal cells. In the clinical trial, doctors will collect a patients own cells, which will then be used in an experimental treatment for age-related macular degeneration. The trial will start with around six patients.

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Light-Detecting Retina Cells Made from Stem Cells