Stories about: macular degeneration

Light-activated nanoparticles could avoid painful eye injections for ‘wet’ macular degeneration

Could intravitreal injections become a thing of the past?
(PHOTO: ZKALILA1998 / WIKIMEDIA COMMONS)

There are two standard treatments for “wet” age-related macular degeneration (AMD), in which abnormal, leaky blood vessels in the back of the eye lead to fluid buildup and vision loss. The first, injection of medication directly into the eye, can be painful and can cause inflammation, infection and detachment of the retina. The second, ablation therapy, uses lasers to destroy the leaky blood vessels. It, too, is unpleasant to undergo, and the lasers can also destroy surrounding healthy tissue, causing further vision loss.

In today’s Nature Communications, the lab of Daniel Kohane, MD, PhD, provides proof-of-concept of a more tolerable alternative: tiny, drug-carrying nanoparticles that can be injected intravenously, but deliver medication only to the eye.

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Age-related macular disease: Is energy starvation a cause?

age-related macular degneration
Hunger distress signal: Energy-starved photoreceptor cones in the retina (colored blue) call for nourishment by releasing a cloud of vascular endothelial growth factor (VEGF; in yellow). The VEGF draws poor-quality, leakage-prone blood vessels (in red), branching from a nearby blood supply. (Image: Jean-Sebastien Joyal)

New insights could potentially change the treatment of two diseases causing blindness: “Wet” age-related macular degeneration (AMD), the leading cause of severe vision loss in Americans over 60, and a less common condition called macular telangiectasia (MacTel) that occurs in middle age.

Both diseases are caused by abnormal growth of misshapen, leaky blood vessels in the eye that damages the macula, the central part of the retina needed to for straight-ahead vision.

The trigger for this pathologic process had been widely thought to be oxygen deprivation. However, findings published today by Nature Medicine suggest another cause: dysfunctional energy metabolism in the eye that starves the retina’s photoreceptors of fuel.

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Blocking bad vessels: A new target for retinopathy, macular degeneration

blood vessels retinopathy

The development of blood vessels is a part of normal growth in almost all tissues. But it can also be pathological: Many eye conditions leading to blindness involve abnormal blood vessel formation, including retinopathy of prematurity in infants, diabetic retinopathy and wet, age-related macular degeneration (AMD).

Blood vessels produced under stress conditions such as inflammation or low oxygen, especially in the retina, are apt to be poorly constructed and leaky. Vascular endothelial growth factor, or VEGF, has been shown to contribute to pathologic vessel growth, and anti-VEGF treatments are now widely used to control the overproliferation of blood vessels, such as Lucentis for wet macular degeneration.

Unfortunately, VEGF-binding antibodies can block not just excess VEGF but the baseline normal amount needed for vessels and neighboring neurons to survive, with potentially serious side effects.

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More accolades for omega 3’s

Omega-3’s are emerging superheroes in the nutrition world. Over two decades ago, scientists noticed that Greenland Eskimos had very low rates of coronary heart disease compared to Western populations. Their secret, it turned out, was eating fish—particularly, fatty fishes like salmon that contain a lot of omega-3 fatty acids.

An avalanche of studies have since demonstrated the cardiovascular health benefits of omega-3 fatty acids, also found in flax seeds and walnuts, as well as suggesting benefits in combating depression, rheumatoid arthritis and some types of cancer, and in boosting cognitive function.

And now comes more evidence that they can prevent blindness.

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