Sunday, August 28, 2011

Mouse-eye view may lead to gene therapy for blindness

Wed, Aug 17 - 4:54 AM

Chronicle Herald

IF YOU’VE EVER wanted to look through someone else’s eyes, you can do it right here in Halifax at Dalhousie’s medical school.

Or, more specifically, you can look through the retina of a mouse. The retina is being kept artificially alive in a dish, fed with oxygen and glucose, and its optic nerve is hooked up to a computer. If you visit Dr. Gautam Awatramani’s lab, you can watch the computer screen and see what the mouse would see if it still had its retina.

Sounds like sci-fi? In fact, Awatramani’s research into vision is so cutting-edge that he was turned down for grants only a few years ago. He said the Canadian Institute of Health Research told him he was crazy and should stick to basic science. Now the neurobiologist’s work, which offers some of science’s best prospects for restoring sight to the blind, is feeding into a booming academic field that is slowly being taken up by biotechnology companies around the world.

Awatramani’s specialty is called optogenetics. Like it sounds, it combines optics, or light, with genes that are tweaked to respond to that light.

In 2008, with friends in a lab in Switzerland, he was part of a scientific breakthrough when his team took genes from green algae, a plant that responds to light, and injected them into the retinas of mice that were predisposed to go blind later in life.

The mice that had been treated with algae genes kept some of their vision while the others went completely blind. The effects of the gene therapy also lasted in the long term as the part of the eye that had degenerated began to express the new gene on its own. Down the road, Awatramani said, he hopes to see a new surgery developed that could do the same for human eyeballs.

"The operation should be very simple. That’s the beauty of the system," he said. "I think it’ll form its own niche, for sure."

The business world might take some time to catch up. Companies have been busy over the last few years developing visual prosthetics, or implants that can help stimulate parts of the eye.

It’s a small field but has attracted a fair amount of attention and investment.

The commercial leader in visual prosthetics, Second Sight Medical Products Inc. in California, made Fast Company magazine’s top-10 list of innovative health companies this year and counts billionaire bioengineer Alfred Mann, who helped develop the cochlear implant for the deaf, among its investors.

Optogeneticists’ attempts to do the same thing — restore some vision to the blind — are slowly starting to win some of that attention, Awatramani said. While the prosthetics stimulate an entire layer of the retina more indiscriminately, feeding the brain information that it finds harder to decipher, algae genes work in a more specific and natural way since they build on the retina’s existing structure.

"It’s a little bit of a crazy idea, but I think people find it less crazy now than they did a handful of years ago," said Alan Horsager, co-founder of a tiny Los Angeles firm called Eos Neuroscience Inc., one of the only companies trying to usher the research through clinical trials.

Horsager said some of the world’s biggest pharmaceutical companies are also looking at gene therapy for the blind. Incorporating genetics into medicine is becoming a more common idea, he said, although no type of gene therapy has been approved for humans yet.

He and his two co-founders at Eos are talking to the U.S. Food and Drug Administration and could bring research like Awatramani’s to market in five to eight years.

"People are coming around and saying, OK, gene therapy isn’t so weird," Horsager said. "You have some data here."

For the medical industry, being able to "light up" specific neurons has far-reaching applications, especially understanding the brain’s more complex patterns.

"The retina’s a piece of brain," Awatramani said in his lab.

"It’s the most accessible part of the brain. We can get to it fast and easily, and from a business perspective, that’s why it’s so attractive for treating neurological disease, because you don’t have to open the skull to get to it."


Saturday, August 20, 2011

Sunglasses should be worn all year to protect eyes from UV rays

We all know the importance of guarding your skin with sunscreen, but what about protecting your eyes on these long, bright summer days? When I think about shielding my peepers with sunglasses, it’s mostly from a style perspective: Can I really pull off those trendy oversize frames? But really, sunglasses should be seen as a health topic.

“We should all be protecting our eyes from both visible light and UV light, throughout our lifetimes, because [sun exposure] can damage structures in the cornea, the lens of the eye and the retina, as well as the skin around the eyes or eyelids,” says Michael Repka, a professor of ophthalmology at the Johns Hopkins University School of Medicine. He notes that studies have shown that ultraviolet exposure can result in increased risk for a range of vision-related problems, from heightened sensitivity to light and irritation to cataracts andpossibly macular degeneration and skin cancers on the eyelid.

Indeed, at my last yearly eye exam, my ophthalmologist informed me that I’d developed pingueculum, small changes to the surface of the eye that look like tiny yellow spots, probably due to chronic UV exposure — perhaps the result of a three-year stint living on a small island, during which I spent a lot of time on boats and only infrequently donned shades. Luckily the condition isn’t usually serious, but my doctor said wearing sunglasses would help prevent it from getting worse.

Eye protection is important all year long, no matter the weather. “Thirty-one percent of UV light still comes through on cloudy days,” says Dora Adamopoulos, an optometrist in Alexandria, who adds that snow-covered surfaces reflect up to 80 percent of UV rays, as opposed to the quarter that are reflected off sand or water.

And certain people run an elevated risk for UV damage, says District optometrist Michael Rosenblatt, who points out that those of us with light-colored irises are particularly susceptible: “If you easily burn in the sun, you should think of yourself as a person who suffers greater damage from UV light in all areas, including your eyes.” Geography is another factor, with people living in the south and at higher elevations tending to get the greatest levels of UV exposure.

Children are also a major concern. “It amazes me that kids go to the beach and their moms are spraying on all this suntan lotion, but they’re running around with no sunglasses on,” says Rosen-blatt. He says that not only are young ones outside often, but that their pupils are larger than adults’ and that, unlike adults, their lenses aren’t able to filter out some UV rays. So just as with skin exposure, “by the time you’re 18 or so, you’ve pretty much done most of the sun-related damage to your eyes,” says Adamopoulos.

That’s not to say that these experts are unsympathetic to the challenges of trying to get children to don shades — children such as my 2-year-old, whose new favorite game involves ripping off his tiny sunglasses and hat as soon as I put them on him, throwing them on the ground, running away and then repeating this action about a thousand times during any park, beach or pool outing. “But you’ve just got to try,” says Rosenblatt.

The best thing we can do to protect ourselves from the cumulative effects of UV exposure on the eyes is to buy properly fitting, comfortable, quality sunglasses — and then wear them as much as possible, along with a wide-brimmed hat. Rosenblatt, for one, recommends frames that extend from the eyebrow to the cheek and wrap around the contour of face, along with lenses that have 100 percent UVA and UVB protection. He also points out that while some contact lenses come with different levels of UV coating, they should all still be worn with sunglasses.

Also be aware that specialized sunglasses can help when you’re engaged in outdoor pursuits such as skiing, sailing or even biking, says Adamopoulos. He says that yellow- and brown-tinted lenses are best on the water, for example, while gray, brown and amber tints work well for field activities, and mirrored coatings are good for snow sports; polarization is a lens treatment that can help reduce glare.

In general, darker isn’t necessarily better, if the lenses don’t have proper UV protection. Says Adamoponous: “You can actually damage your eyes if there isn’t proper UV coverage, because darker lenses cause your pupils to get bigger to see,” which results in increased UV exposure in the retina.

As for the cost of sunglasses, know that you don’t always get what you pay for. “Sometimes the most expensive glasses are worse than cheapest, in terms of filtering UVA and UVB light,” explains Repka, so checking those sticker labels on lenses about UVA and UVB protection is key.

I just invested in a pricey pair of designer, Jackie O-style sunglasses with polarized lenses that seem to make the world appear quite a bit crisper, as if my vision has actually improved. My hope is that looking good will inspire me to wear them more often — and inspire my kids to follow suit with their own shades. If not, at least I can count on the cardio benefits of chasing after my little one with his sunglasses and hat.

Friday, August 12, 2011

Type 2 diabetes in newly diagnosed 'can be reversed'

An extreme eight-week diet of 600 calories a day can reverse Type 2 diabetes in people newly diagnosed with the disease, says a Diabetologia study.

Newcastle University researchers found the low-calorie diet reduced fat levels in the pancreas and liver, which helped insulin production return to normal.

Seven out of 11 people studied were free of diabetes three months later, say findings published in the journal.

More research is needed to see whether the reversal is permanent, say experts.

Type 2 diabetes affects 2.5m people in the UK. It develops when not enough insulin is produced in the body or the insulin that is made by the body doesn't work properly.

When this happens, glucose - a type of sugar - builds up in the blood instead of being broken down into energy or fuel which the body needs.

The 11 participants in the study were all diagnosed with Type 2 diabetes within the previous four years.

They cut their food intake drastically for two months, eating only liquid diet drinks and non-starchy vegetables.

Fat loss

After one week of the diet, researchers found that the pre-breakfast blood sugar levels of all participants had returned to normal.

MRI scans of their pancreases also revealed that the fat levels in the organ had decreased from around 8% - an elevated level - to a more normal 6%.

Three months after the end of the diet, when participants had returned to eating normally and received advice on healthy eating and portion size, most no longer suffered from the condition.

Professor Roy Taylor, director of Newcastle Magnetic Resonance Centre at Newcastle University and lead study author, said he was not suggesting that people should follow the diet.

"This diet was only used to test the hypothesis that if people lose substantial weight they will lose their diabetes.

"Although this study involved people diagnosed with diabetes within the last four years, there is potential for people with longer-standing diabetes to turn things around too."

Susceptibility question

Dr Ee Lin Lim, also from Newcastle University's research team, said that although dietary factors were already known to have an impact on Type 2 diabetes, the research showed that the disease did not have to be a life sentence.

"It's easy to take a pill, but harder to change lifestyle for good. Asking people to shift weight does actually work," she said.

However, not everyone in the study managed to stay free of diabetes.

"It all depends on how much individuals are susceptible to diabetes. We need to find out why some people are more susceptible than others, then target these obese people. We can't know the reasons for that in this study," Dr Lim said.

Professor Edwin Gale, a diabetes expert from the University of Bristol, said the study did not reveal anything new.

"We have known that starvation is a good cure for diabetes. If we introduced rationing tomorrow, then we could get rid of diabetes in this country.

"If you can catch people with diabetes in the early stages while beta cells are still functioning, then you can delay its onset for years, but you will get it sooner or later because it's in the system."

But Keith Frayn, professor of human metabolism at the University of Oxford, said the Newcastle study was important.

"People who lose large amounts of weight following surgery to alter their stomach size or the plumbing of their intestines often lose their diabetes and no longer need treatment.

"This study shows that a period of marked weight loss can produce the same reversal of Type 2 diabetes.

"It offers great hope for many people with diabetes, although it must be said that not everyone will find it possible to stick to the extremely low-calorie diet used in this study."

Dr Iain Frame, director of research at Diabetes UK, which funded the study, said the diet was not an easy fix.

"Such a drastic diet should only be undertaken under medical supervision. Despite being a very small trial, we look forward to future results particularly to see whether the reversal would remain in the long term."

Thursday, August 4, 2011

Virtual White Cane for the Blind

The Hebrew University of Jerusalem recently unveiled a new "virtual cane" that allows blind users to reconstruct a more accurate image of their surroundings than with a traditional white cane.

Its basic operating principle is quite simple. The cane emits a beam at objects around the user and transmits the information to him or her as a gentle vibration. The cane's sensors allow the blind person to assess the height and distance of the surrounding objects. The accuracy of the reconstruction of the person's surroundings increases his or her safety. Moreover, the virtual cane is quite small, making it easier to carry than a white cane, and it can function for up to 12 hours before needing to be recharged.

Dr. Amir Amedi's team has tested the virtual cane in a variety of situations, including a maze. While ensuring that the cane was effective was an objective, the research primarily aimed at studying how the brain of the blind functioned, particularly with respect to brain reorganization. The tests demonstrated that using the virtual cane was very intuitive and could be mastered in just a few minutes.