Featured Research

from universities, journals, and other organizations

Study Shows Bacterium Present In Eyes With 'Wet' Age-related Macular Degeneration

Date:
November 10, 2005
Source:
Massachusetts Eye And Ear Infirmary
Summary:
Researchers at the Massachusetts Eye and Ear Infirmary (MEEI) have found that Chlamydia pneumoniae, a bacterium linked to heart disease and capable of causing chronic inflammation, was present in the diseased eye tissue of five out of nine people with neovascular, or “wet,” age-related macular degeneration (AMD).

Researchers at the Massachusetts Eye and Ear Infirmary (MEEI) have found that Chlamydia pneumoniae, a bacterium linked to heart disease and capable of causing chronic inflammation, was present in the diseased eye tissue of five out of nine people with neovascular, or “wet,” age-related macular degeneration (AMD). However, it was not found in the eyes of more than 20 individuals without AMD, providing more evidence that this disease may be caused by inflammation. The study is described in the November issue of Graefe’s Archive for Clinical and Experimental Ophthalmology.

Related Articles


AMD is the leading cause of blindness in Americans over the age of 55. The majority of vision loss is due to neovascular AMD, the advanced form of the disease characterized by the formation of blood vessels in the macula, the center part of the eye’s retina. These blood vessels often leak, thus giving neovascular AMD the name of “wet” AMD.

Researchers at the MEEI and Harvard Medical School (HMS) examined nine wet AMD membranes for the presence of C. pneumoniae and also determined whether this pathogen can change the function of eye cells in ways that can cause wet AMD. They found C. pneumoniae in the eyes of five out of the nine patients with wet AMD. They also tested tissue from more than 20 people who did not have AMD and did not find C. pneumoniae in any of these normal eye tissues.

“The paper showed that C. pneumoniae is capable of modifying the function of important cell types involved in regulating normal eye function,” said lead author Murat Kalayoglu, MD, PhD. “We found that C. pneumoniae infection led to increased production of vascular endothelial growth factor (VEGF), the key protein involved in wet AMD. That C. pneumoniae infection of human eye cell types increases VEGF production is therefore significant and could explain in part why VEGF levels are increased in many people with wet AMD.” Kalayoglu is an HMS research fellow in ophthalmology at MEEI.

Most of the new medications either marketed or being developed to treat wet AMD, such as Macugen (EyeTech Pharmaceuticals) and Lucentis (Genetech) block VEGF.

The study comes at a time of great interest in inflammatory mediators of AMD. Over the past seven months, a flurry of high-impact papers have shown, in aggregate, that nearly 50 percent of AMD can be explained by variations in a gene called Complement Factor H (CFH). This gene makes a protein that regulates the immune and inflammatory responses of the body.

“Our hypothesis is that C. pneumoniae may be the key link between CFH and AMD,” Kalayoglu said. “That is, patients with CFH variations may be particularly susceptible to the damaging effects of chronic infection, and an infectious organism like C. pneumoniae may be particularly effective in accelerating inflammation and driving progression of AMD in these patients.”

Kalayoglu and colleagues are currently collaborating with CFH researchers to study this hypothesis. “It may be possible to stop or reverse progression of AMD by identifying susceptible patients by diagnostic testing, and then treating these susceptible patients. Although C. pneumoniae is a bacterium that might respond to some antibiotics, much more work needs to be done before considering antibiotic therapy for AMD,” he said.

“This is an important study suggesting that infection with C. pneumoniae may be a critical link between a genetic predisposition to AMD and actual progression to disease,” said Gerald I. Byrne, Ph.D., professor and chairman of the Department of Molecular Sciences, University of Tennessee Health Sciences Center. “This is yet another example of how an infection may unexpectedly contribute to a chronic disease. Certainly the association of C. pneumoniae with heart disease sets the stage for this pathogen’s involvement in other chronic conditions. This work is, in some ways, reminiscent of studies done more than 15 years ago on infections and ulcers. Those studies were viewed with skepticism, but Drs. Marshal and Warren, the researchers who pioneered that work received the Nobel Prize this year.”

The Graefe’s paper builds on data from the same group that showed, for the first time, that an infectious agent is associated with AMD by epidemiological studies (Archives of Ophthalmology, April 2003).


Story Source:

The above story is based on materials provided by Massachusetts Eye And Ear Infirmary. Note: Materials may be edited for content and length.


Cite This Page:

Massachusetts Eye And Ear Infirmary. "Study Shows Bacterium Present In Eyes With 'Wet' Age-related Macular Degeneration." ScienceDaily. ScienceDaily, 10 November 2005. <www.sciencedaily.com/releases/2005/11/051110221819.htm>.
Massachusetts Eye And Ear Infirmary. (2005, November 10). Study Shows Bacterium Present In Eyes With 'Wet' Age-related Macular Degeneration. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2005/11/051110221819.htm
Massachusetts Eye And Ear Infirmary. "Study Shows Bacterium Present In Eyes With 'Wet' Age-related Macular Degeneration." ScienceDaily. www.sciencedaily.com/releases/2005/11/051110221819.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Best Tips to Curb Holiday Carbs

The Best Tips to Curb Holiday Carbs

Buzz60 (Dec. 19, 2014) It's hard to resist those delicious but fattening carbs we all crave during the winter months, but there are some ways to stay satisfied without consuming the extra calories. Vanessa Freeman (@VanessaFreeTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Sierra Leone Bikers Spread the Message to Fight Ebola

Sierra Leone Bikers Spread the Message to Fight Ebola

AFP (Dec. 19, 2014) More than 100 motorcyclists hit the road to spread awareness messages about Ebola. Nearly 7,000 people have now died from the virus, almost all of them in west Africa, according to the World Health Organization. Video provided by AFP
Powered by NewsLook.com
Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Buzz60 (Dec. 19, 2014) A double-amputee makes history by becoming the first person to wear and operate two prosthetic arms using only his mind. Jen Markham has the story. Video provided by Buzz60
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