Posts tagged macular degeneration
Articles and news from the latest research reports.
New cells found that could help save people’s sight
Eye experts and scientists at the University of Southampton have discovered specific cells in the eye which could lead to a new procedure to treat and cure blinding eye conditions.
Led by Professor Andrew Lotery, the study found that cells called corneal limbal stromal cells, taken from the front surface of the eye have stem cell properties and could be cultured to create retinal cells.
This could lead to new treatments for eye conditions such as retinitis pigmentosa or wet age-related macular degeneration, a condition which is a common cause of loss of vision in older people and will affect around one in three people in the UK by age 70.
Furthermore the research, published in the British Journal for Ophthalmology, suggests that using corneal limbus cells would be beneficial in humans as it would avoid complications with rejection or contamination because the cells taken from the eye would be returned to the same patient.
Professor Lotery, who is also a Consultant Ophthalmologist at Southampton General Hospital, comments: “This is an important step for our research into the prevention and treatment of eye conditions and blindness.
“We were able to characterize the corneal limbal stromal cells found on the front surface of the eye and identify the precise layer in the cornea that they came from. We were then successful in culturing them in a dish to take on some of the properties of retinal cells. We are now investigating whether these cells could be taken from the front of the eye and be used to replace diseased cells in the back of the eye in the retina. If successful this would open up new and efficient ways of treating people who have blinding eye conditions.”
This is a promising discovery as the corneal limbus is one of the most accessible regions of the human eye and it represents 90 per cent of the thickness of the front eye wall. Therefore cells could be easily obtainable from this area with little risk to the patient’s eye and sight. However Professor Lotery says more research is needed to develop this approach before they are used in patients.
(Source: southampton.ac.uk)
Cells from Skin Create Model of Blinding Eye Disease
For the first time, Wisconsin researchers have taken skin from patients and, using induced pluripotent stem cell (iPSC) technology, turned them into a laboratory model for an inherited type of macular degeneration.
Dr. David Gamm, director of the University of Wisconsin-Madison’s McPherson Eye Research Institute, said that while Best disease is relatively rare, having a patient-specific model of the eye disease, which destroys the macula of the retina, could lead to a greater understanding of more common eye disorders such as age-related macular degeneration.
“This model gives us a chance to understand the biological effects of human gene mutations in a relatively expeditious manner,” says Gamm, associate professor of ophthalmology and visual sciences and pediatrics at the UW School of Medicine and Public Health. “Ultimately, we hope the model will help us craft treatments to slow or reverse the course of Best disease.”
Nobel Winner’s Stem Cells to Be Tested in Eye Malady in 2013
Stem cells derived from a mouse’s skin won Shinya Yamanaka the Nobel Prize. Now researchers in Japan are seeking to use his pioneering technology for an even greater prize: restoring sight.
Scientists at the Riken Center for Developmental Biology in Kobe plan to use so-called induced pluripotent stem cells in a trial among patients with macular degeneration, a disease in which the retina becomes damaged, resulting in loss of vision, Yamanaka told reporters in San Francisco.
Companies including Pfizer Inc. (PFE) are already planning trials of stem cells derived from human embryos. The Japanese study will be the first to use a technology that mimics the power of embryonic cells while avoiding the ethical controversy that accompanies them.
“The work in that area looks very encouraging,” John B. Gurdon, 79, a professor at the University of Cambridge who shared the Nobel with Yamanaka, said in an interview in London.
Yamanaka and Gurdon shared the 8 million Swedish kronor ($1.2 million) award for experiments 50 years apart that showed that mature cells retain in latent form all the DNA they had as immature stem cells, and that they can be returned to that potent state, offering the potential for a new generation of therapies against hard-to-treat diseases such as macular degeneration.
Easier test for blindness cause
Scientists from Australia’s Vision Centre have demonstrated a quick, accurate test under lights for one of the world’s leading causes of blindness.
A new study shows that age-related macular degeneration (AMD) can be just as effectively and more rapidly and inexpensively diagnosed under bright lights, instead of requiring patients to sit for 20 minutes in a darkened room.
“AMD accounts for half of the legal blindness cases in Australia,” says Professor Ted Maddess from The Vision Centre and The Australian National University. “It affects one in seven people over the age of 50, costing the nation $2.6 billion a year. Globally, it affects 25 to 30 million people, with an annual cost of $343 billion.
“While current tests for AMD are done in the light, scientists have proposed that it might be better if the patient has their vision adapted to the dark prior to the test,” he says.
“This is because they had found that rod receptors – vision cells that we use to see in black and white and in low light – die earlier in AMD than the cone receptors we use to see in colour during the day. So it had been suggested that AMD tests would be more accurate if they were based on the health of a person’s rods.”
Surgeons at UC Davis Medical Center have successfully implanted a new telescope implant in the eye of a patient with end-stage age-related macular degeneration (AMD), the most advanced form of the disease and a leading cause of blindness in older Americans.
The device, approved by the Food and Drug Administration in 2010, is the only medical/surgical option available that restores a portion of vision lost to the disease. UC Davis Health System’s Eye Center, in collaboration with the Society for the Blind, is one of the few in California and the nation to offer the innovative procedure.
Vision cells, not brain, to blame for colour blindness
The real culprits of colour blindness are vision cells rather than unusual wiring in the eye and brain, recent research has shown.
The discovery brings scientists a step closer to restoring full colour vision for people who are colour blind – a condition that affects close to two million Australians, says Professor Paul Martin from The Vision Centre and The University of Sydney.
It may also help pave the way for an answer to one of the most common causes of blindness – age-related macular degeneration (AMD), which accounts for half of the legal blindness cases in Australia.
“There are millions of cones in our eyes – vision cells that pick up bright light and allow us to see colour,” Prof. Martin says. “They are nicknamed red, green and blue cones because they are sensitive to different wavelengths of light.
“We now know that in the macular region of the eye, each cone has its own ’private line’ into the optic nerve and the brain. Just as a painter can mix from three tubes of paint to produce a wide and vivid palette, our brain uses the ‘private lines’ from the three cone types to create thousands of colour sensations.
Scientists previously thought that full colour vision depends on specialised nerve wiring in the eye and brain, but animal studies show that the wiring is identical for monkeys whether they have normal or abnormal colour vision, Prof. Martin says.
“This tells us that there’s nothing wrong in the brain – it’s only working with the signals that it receives on the ‘private lines’,” he says. “So the only difference in normal and abnormal colour vision is caused by the first stage of sight, which points to faulty cones. Either they have failed to develop, or else they are picking up abnormal wavelengths.
“Now that we know faulty wiring isn’t the cause, we can concentrate on fixing the cones, which are controlled by genes – and thus prone to mutation or mistakes during cell replication. There are already promising results from gene therapy as a way to restore full colour vision in colour blind monkeys.”
“While we have still have some way to go, the benefits of this gene therapy – if successful – can potentially extend beyond providing complete colour vision,” he says.
“If we can get these genes to work in human eyes, it means that the same approach might be possible for other visual problems – including blinding diseases such as macular degeneration.”
"In macular degeneration, energy supplies to the macula can’t keep up with demand. So the ‘private line’ system must be very energy-intensive. Gene therapy could be used to turn down the cones’ energy demand, or to increase energy supply from supporting cells to cone cells,” Prof. Martin says.
“Together with clinical researchers at the Save Sight Institute, we are now working hard to find out exactly how many ‘private lines’ there are in humans. That can point us to where energy demand is highest and we can target gene therapy to the right place.
"So animal research on ‘private lines’ for colour vision has given new clues for understanding one of the most important visual diseases – macular degeneration – in humans."
(Source: scinews.com.au)
Implantable Telescope Technology
Implantable Miniature Telescope along with the cornea, enlarges images in front of the eye approximately 2.2 or 2.7 times their normal size (depending on the model used). The magnification allows central images to be projected onto healthy perimacular areas of the retina instead of the macula alone, where breakdown of photoreceptors and loss of vision has occurred. This helps reduce the ‘blind spot’ and allows the patient to distinguish and discern images that may have been unrecognizable or difficult to see.
The telescope is about the size of a pea (3.6 mm diameter; 4.4 mm length) and is surgically placed inside the eye.