Featured Research

from universities, journals, and other organizations

Sight fails when defective eye cells cripple renewal

Date:
September 7, 2011
Source:
Case Western Reserve University
Summary:
In the rare eye disease, Enhanced S-Cone Syndrome, the retina degenerates because light-receiving cells fail to regenerate, new research shows. The discovery provides a target to treat the disease, which affects about one in 1 million people. But, the findings and the scientists' use of two technologies to uncover the mechanisms leading to sight loss may help gain understanding of other retinal degenerative diseases, including macular degeneration, affecting millions worldwide.

In a rare eye disease, the retina degenerates because light-receiving cells fail to regenerate, research led by a student at Case Western Reserve University School of Medicine shows.

Related Articles


The researchers include Dr. Samuel G. Jacobson's group at the University of Pennsylvania and Dr. Andreas Engel's group at University of Basel, Switzerland. They found that when the natural renewal process fails, metabolites are locked in, build up and turn toxic, killing cells over time in Enhanced S-Cone Syndrome.

A description of their work is online and will be published in print in the Journal of the Federation of American Societies for Experimental Biology on September 1.

The discovery provides a target to treat and prevent blindness caused by the disease, also known as Goldmann-Favre Syndrome, which is found in about one in 1 million people.

But, more importantly the researchers say, the findings and the scientists' use of two technologies to uncover the mechanisms leading to sight loss may help gain understanding of a broad array of retinal degenerative diseases, including macular degeneration, affecting millions worldwide.

"Although rare, Enhanced S-Cone Syndrome helps us understand critical visual processing errors that arise in disease," said Debarshi Mustafi, who is earning his medical degree and PhD in pharmacology at Case Western Reserve. He is lead author of the study. "Knowing that photoreceptor cells affect their own renewal will surely have an impact on other, more common, forms of retinal degeneration."

Enhanced S-Cone Syndrome is a condition in which the eye no longer has an orderly balance of cells called rods and cones, which enable us to see lights of different wavelengths, that is, different colors. Instead, cones that receive short wavelength light dominate and are clumped throughout the retina.

Those with the disease become night blind and progressively develop blind spots and lose sight as they age, until reaching blindness.

Genes connected to the disease have been known for some time. To find the molecular mechanism that causes sight loss, the researchers examined mouse models of the disease and 9 patients with the syndrome.

Optical imaging of the patients over a decade revealed an abnormal interface between the cones and the adjacent layer of tissue, called the retinal pigment epithelium.

Using gene-sequencing techniques on the mouse models, the team found expression of 30 genes involved in sight differed in healthy mice versus the disease models. Three of the genes were engaged in renewal of photoreceptors, a process called phagocytosis.

The researchers used a scanning electron microscope to produce images down to 100 nanometers, or the size of the largest holes in a surgical mask.

They found no phagosomes, essentially compartments made in cone cell membranes in which specialized cells called phagocytes of the retinal pigment epithelium eat cone material. In a healthy retina, phagosomes are present; phagocytes eat about 10 percent of the cone per day, continually renewing the cone.

The images instead showed bulbous cones in which metabolites that would normally be consumed remain, causing the swelling and turning toxic, the researchers said.

Analysis of cell cultures confirmed aberrations in the cones themselves were the cause of the problem, not the adjacent pigment layer as was previously thought.

"What we learn from this inherited human disease, and its mouse model, will be helpful to understand the aging process of the retina, like that seen in age-related macular degeneration," said Krzysztof Palczweski, John H. Hord Professor and chair of the Department of Pharmacology at CWRU School of Medicine. Palzcweski is Mustafi's advisor and senior author of the paper. "It is very likely that the phagocytotic process described in Debarshi's paper is a dysfunction as we age."

Mustafi said the methods that led to the discovery -- combining gene sequencing and imaging -- may have a wider impact. "It is a new way to study any disease."


Story Source:

The above story is based on materials provided by Case Western Reserve University. Note: Materials may be edited for content and length.


Journal Reference:

  1. D. Mustafi, B. M. Kevany, C. Genoud, K. Okano, A. V. Cideciyan, A. Sumaroka, A. J. Roman, S. G. Jacobson, A. Engel, M. D. Adams, K. Palczewski. Defective photoreceptor phagocytosis in a mouse model of enhanced S-cone syndrome causes progressive retinal degeneration. The FASEB Journal, 2011; 25 (9): 3157 DOI: 10.1096/fj.11-186767

Cite This Page:

Case Western Reserve University. "Sight fails when defective eye cells cripple renewal." ScienceDaily. ScienceDaily, 7 September 2011. <www.sciencedaily.com/releases/2011/09/110901105417.htm>.
Case Western Reserve University. (2011, September 7). Sight fails when defective eye cells cripple renewal. ScienceDaily. Retrieved March 6, 2015 from www.sciencedaily.com/releases/2011/09/110901105417.htm
Case Western Reserve University. "Sight fails when defective eye cells cripple renewal." ScienceDaily. www.sciencedaily.com/releases/2011/09/110901105417.htm (accessed March 6, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, March 6, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Bupa Eyes India Healthcare Opportunities

Bupa Eyes India Healthcare Opportunities

Reuters - Business Video Online (Mar. 5, 2015) Bupa is hoping to expand in India&apos;s fast-growing health insurance market, once a rule change on foreign investment is implemented. The British private healthcare group&apos;s CEO tells Grace Pascoe why it&apos;s so keen on the new opportunity. Video provided by Reuters
Powered by NewsLook.com
Doctor in Your Pocket Is Getting Smarter

Doctor in Your Pocket Is Getting Smarter

Reuters - Business Video Online (Mar. 5, 2015) Mobile apps are turning smartphones into a personal doctors, with users able to measure heart rate, blood pressure and even blood sugar. But will it change our behaviour? Ivor Bennett reports from the Mobile World Congress in Barcelona. Video provided by Reuters
Powered by NewsLook.com
AbbVie Inks $21B Deal To Buy Cancer Drugmaker Pharmacyclics

AbbVie Inks $21B Deal To Buy Cancer Drugmaker Pharmacyclics

Newsy (Mar. 5, 2015) AbbVie announced Wednesday it will buy cancer drugmaker Pharmacyclics in a $21 billion deal. Video provided by Newsy
Powered by NewsLook.com
Toddlers Drinking Coffee? Why You Shouldn't Share Your Joe

Toddlers Drinking Coffee? Why You Shouldn't Share Your Joe

Newsy (Mar. 5, 2015) A survey of Boston mothers and toddlers found that 15 percent of two-year-olds drink coffee and 2.5 percent of 1-year-olds. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins