Loss of anti-aging gene possible culprit in age-related macular degeneration

A team of researchers at Georgetown University Medical Center (GUMC) has found that loss of an anti-aging gene induces retinal degeneration in mice and might contribute to age-related macular degeneration, the major cause of blindness in the elderly.

In the Oct. 9 issue of the Journal of Neuroscience, the scientists demonstrated a key role for the aging-suppressor gene Klotho in maintaining the health of the mouse and . They say that in their animal studies, loss of Klotho expression leads to characteristics observed in both kinds of —wet and dry—seen in humans.

Klotho, a hormone that is synthesized and secreted by some organs and tissues, is being studied worldwide for its anti-aging properties. A Japanese researcher discovered 15 years ago that when Klotho is mutated, a mouse that should live two years survives for only two months. Transgenic mice that overexpress the Klotho gene have a longer-than-expected lifespan.

"We found four important functions Klotho provides in the human retina, which leads us to believe that the gene is crucial to the health of this light sensitive tissue," says the study's senior investigator, Nady Golestaneh, PhD, assistant professor of ophthalmology, neurology, biochemistry and molecular & cellular biology at GUMC.

They found that Klotho increases the activity of genes that synthesize the light absorbing visual pigments in the retinal cells. Klotho also increases the expression of that protect against the oxidative stress known to damage the retina, and which can lead to dry macular degeneration. Klotho inhibits the vascular endothelial growth factor and therefore, might play an important role in inhibiting the overgrowth of blood vessels in the eye, a major cause of wet macular degeneration.

Klotho also regulates phagocytosis of the outer segment of photoreceptors in the retina. This process allows the photoreceptors to renew themselves, and if that function is abolished, the photoreceptors degenerate and die causing blindness.

"For these reasons, we believe Klotho might be an interesting therapeutic target for age-related macular degeneration," Golestaneh says. "Gene therapy or cell therapy might be able to induce new expression of Klotho in the aging retina."

But she adds that before these strategies can be tested, research that quantifies the decline of Klotho expression in human eyes, and directly links this dysfunction to macular degeneration, must be undertaken.

Related Stories

A new treatment for kidney disease-associated heart failure?

Jan 09, 2013

Chronic kidney disease (CKD) patients frequently suffer from mineral bone disorder, which causes vascular calcification and, eventually, chronic heart failure. Similar to patients with CKD, mice with low levels of the protein ...

Anti-aging gene linked to high blood pressure

Aug 19, 2009

Researchers at the University of Oklahoma Health Sciences Center have shown the first link between a newly discovered anti-aging gene and high blood pressure. The results, which appear this month in the journal ...

Anti-aging hormone Klotho may prevent complications

Feb 18, 2011

Low levels of the anti-aging hormone Klotho may serve as an early warning sign of the presence of kidney disease and its deadly cardiovascular complications, according to findings by UT Southwestern Medical Center researchers.

Recommended for you

Neurons in human skin perform advanced calculations

15 hours ago

Neurons in human skin perform advanced calculations, previously believed that only the brain could perform. This is according to a study from Umeå University in Sweden published in the journal Nature Ne ...

Memory in silent neurons

Aug 31, 2014

When we learn, we associate a sensory experience either with other stimuli or with a certain type of behavior. The neurons in the cerebral cortex that transmit the information modify the synaptic connections ...

Why your favourite song takes you down memory lane

Aug 28, 2014

Music triggers different functions of the brain, which helps explain why listening to a song you like might be enjoyable but a favourite song may plunge you into nostalgia, scientists said on Thursday.

User comments