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Entries in Macular Degeneration (3)

Monday
Feb272012

Research Offers Hope for Halting Macular Degeneration

Reporter's Notebook
By: Jane E. Allen

iStockphoto/Thinkstock(NEW YORK) -- I grew up acutely aware that good vision is precious.

In 1971, at age 46, my mother lost sight in her right eye from a blood clot in the retina. It happened within minutes, and over the years, glaucoma and cataracts took their toll, although she continued plowing through murder mysteries with what she called her “good eye.”

Then, one night in December 2008, Mom casually mentioned that bar codes on food packages looked wavy. I knew visual distortions were a sentinel symptom of age-related macular degeneration (AMD), a leading cause of blindness, and urged her to see her ophthalmologist. Within 36 hours, a retina specialist was injecting a drug called Lucentis into her left eye to protect her central vision and ability to see detail. Since then, my 86-year-old mother has returned every six weeks for an injection of Lucentis, which has largely stabilized the so-called wet form of the disease.

As if having one parent with severe eye disease isn’t troubling enough, my 89-year-old father has been treated for glaucoma, cataracts and the so-called dry form of macular degeneration. However, his vision is so stable that he long ago stopped checking for crooked lines on what’s called an Amsler grid, which he taped inside a kitchen cabinet door more than 25 years ago.

According to the National Eye Institute, more than 1.75 million Americans, aged 40 and older have advanced AMD. There are treatments, but there is no cure -- at least not yet.

Despite my own elevated risk for the disease, stemming from age and family history, this week I got a glimmer of hope that science may keep me from following in my parents’ footsteps. Researchers from UC Santa Barbara, the University of Utah and the University of Iowa reported finding 50 genes that were either overly active or less active in a comparison of donor eyes with and without macular degeneration. The findings are illuminating little-understood aspects of how macular degeneration begins and progresses, according to a study published Thursday in BioMed Central’s journal Genome Medicine.

Not only can these genes “identify people with clinically recognized AMD and distinguish between different advanced types,” some of them also appear linked to abnormal changes occurring in the eye before the disease is diagnosable, said study author Monte J. Radeke, a research scientist at UCSB’s Center for the Study of Macular Degeneration. Knowing how these genes function makes them potentially valuable targets for drug development, he said.

“That’s the most important thing about this article. It points out different pathways that could be involved in the disease progression,” said Dr. Marco Zarbin, chief of ophthalmology at the University of Medicine and Dentistry of New Jersey in Newark. “This is wonderful research because first of all, it shows a number of pathways involved in the disease process, both in the early and later stages, which creates opportunities to create treatments that might be better than what we have now.”

Eye doctors currently cannot really help someone at high risk who hasn’t yet manifested signs of the disease. In addition, the current treatment arsenal remains limited, although some of the many drugs now in clinical trials might potentially prove useful, Zarbin said.

Doctors can halt or slow the progression of wet AMD with injections of Lucentis (ranibizumab), approved in 2005; Avastin (bevacizumab), used off-label; and Eylea (aflibercept), FDA-approved last November. All three drugs, which prevent growth of abnormal and leaky vessels in the retina, appear more effective than Macugen (pegaptanib), which was approved in 2004. A few patients still receive photodynamic therapy with Visudyne (verteporfin), an intravenous drug approved in 2000 that’s activated by light shined into the eye. Patients with some manifestations of dry AMD, such as deposits called drusen, can stave off vision loss by taking a dietary supplement of minerals and vitamins.

Researchers around the globe have found some genes associated with a predisposition to AMD, but the new study “increases our knowledge of the genetic abnormalities that are associated with the different stages of AMD. You’re basically increasing the genetic fingerprint for at-risk patients,” Zarbin said. It’s still too soon to make the information the basis of a screening test, he said.

“If we had perfect treatment for all stages of disease, and perfect treatments that could prevent development of disease before you get it, then genetic screening would make a lot of sense,” Zarbin added.

By identifying genes involved in processes that damage the eye, the findings set the stage for a more sophisticated, multi-pronged approach to treatment. Doctors could develop therapies that target genes associated with inflammation, genes that control programmed cell death (apoptosis) in dry AMD, and genes that drive the formation of leaky blood vessels (angiogenesis) in wet AMD. Doctors might prescribe multiple drugs, kind of like hitting your enemy on several fronts.

Zarbin and Dr. Kang Zhang, director of the Institute for Genomic Medicine and chief of Ophthalmic Genetics at UC San Diego, said they’d like to see the study replicated in larger numbers.

”What I want to see is more connections between genes which give you heightened genetic risk for AMD and the genes identified by these authors,” Zhang said.

Finally, Zhang said one of the practical limitations of the new findings was that they came from cadaver eyes. “It’s not feasible to biopsy human eyes,” he said. He hopes the same kinds of genetic information might be gleaned from blood samples and eventually turned into simple blood tests.

I’m hoping that diagnostic, therapeutic and preventive advances will keep me from ever having to face a needlestick in the eye eight times a year. Unfortunately, I didn’t inherit my mother’s remarkable ability to tolerate pain and discomfort.

Copyright 2012 ABC News Radio

Monday
Jan232012

Blindness Treatment an Embryonic Stem Cell First

Jupiterimages/Thinkstock(BOSTON) -- The first results of human embryonic stem cell therapy are in, and they look good.

Two women, 51 and 78, who were legally blind became the first patients to receive human embryonic stem cell treatment, for their condition. The treatment, also called hESC-RPE, involved scientists injecting stem cells into each patient’s eye. One woman had a condition known as Stargardt’s macular dystrophy and the other had age-related macular degeneration. Both conditions cause severe vision loss. The surgery appeared safe after four months and both women experienced an improvement in vision.

“Our study is designed to test the safety and tolerability of hESC-RPE in patients with advanced-stage Stargardt’s macular dystrophy and dry age-related macular degeneration,” the authors wrote. “So far, the cells seem to have transplanted into both patients without abnormal proliferation...or other untoward pathological reactions or safety signals. Continued follow-up and further study is needed. The ultimate therapeutic goal will be to treat patients earlier in the disease processes, potentially increasing the likelihood of photoreceptor and central visual rescue.”

Eye experts say this is an important study because it could show a promising trend in vision improvement. According to the National Eye Institute, about 1.75 million Americans currently suffer from macular degeneration, and this number is expected to grow to 2.95 million in 2020.

“Stem cell biology has an enormous potential to correct genomically derived ocular diseases, both in correcting deficiencies and amending altered anatomy and physiology,” said Barrett Katz, Frances DeJur Chair in ophthalmology at Montefiore Medical Center in New York. “The eye is the very best organ to expect such advances to be made within, as it is relatively easily accessible and immunologically privileged.”

The research, conducted at UCLA and Advanced Cell Technology in Massachusetts and published Monday in Lancet, was small in scope and population and no patients were given a placebo treatment for the sake of comparison.

For this reason, some doctors worried the report would raise hopes prematurely.

“To reach any conclusions on the safety or efficacy of two patients treated for four months without a control population for comparison is unreasonable,” said Martin Friedlander, professor of ophthalmology at Scripps Health in La Jolla, Calif. “This is why anecdotal reports like this are not published.”

“This falsely raises the hopes of millions of individuals suffering from these diseases,” he said.

The use of human embryonic stem cells has long been seen as an ethically controversial medical technology because many ague that an embryo is the earliest form of life. Extracting stem cells from that embryo almost always damages it.

But proponents of the use of human embryonic stem cells say this argument lacks validity and detracts from the medical benefits that could be achieved.

Copyright 2012 ABC News Radio

Thursday
Dec022010

Scientisits 'See' New Benefit in Fish Diets

Photo Courtesy - Getty Images(BALTIMORE) -- Eating fish may be the key to saving your eyesight.

Researchers at Johns Hopkins School of Medicine in Baltimore claim that the onset of age-related macular degeneration, or AMD, might be minimized by a diet rich in omega-3 fatty acids, which fish have in abundance.

AMD is prevalent in seniors and is the major cause of blindness in Caucasians.

Lead study author Sheila K. West reported a study of 2,400 people between the ages of 65 and 84 revealed that those who ate less omega-3-rich fish and shellfish were more prone to contracting AMD and being in the advanced stages of the disease.

Seniors in the study group lived in Maryland's Eastern Shore region, where fish and shellfish are a dietary staple.

Copyright 2010 ABC News Radio







ABC News Radio