Fruit Fly Clues Help Fight Macular Degeneration

Fruit Fly Clues Help Fight Macular Degeneration

The genetic makeup of the humble fruit fly surprisingly holds one of the closest relationships to the human genome. Upwards of 75% of genes that cause disease in humans can be found in this freckle of a creature. Fruit flies, aka drosophila, are inexpensive to keep and have easily identifiable ‘polytene’ chromosomes which allow scientists to view directly under a microscope.

Recently, new information regarding fruit fly eye anatomy continues to validate information gained from using this species for research.

According to the National Institutes of Health (NIH),

“Six biological pigments called rhodopsins [light-sensitive receptor proteins involved in visual phototransduction aka light converted into electrical signals] play well-established roles in light-sensing in the fruit fly eye. Three of them also have light-independent roles in temperature sensation. New research shows that a seventh rhodopsin, Rh7, is expressed in the brain of fruit flies where it regulates the fly’s day-night activity cycles.”

Lisa Neuhold, Ph.D., program director at the National Eye Institute commented,

“This newly discovered role for Rh7 could have clinical implications down the road. Identifying new roles for light-sensitive opsins [a group proteins made light-sensitive via the chromophore retinal found in photoreceptor cells of the retina] is essential for understanding degenerative retinal disorders [such as macular degeneration] and developing potential new treatments,”

These and many other research studies of fruit fly optics shows some promising clues to help fight macular degeneration. Once again this almost invisible species steps up, this time as one of the giants of retinal disease research.

Blue and Violet Light Re-Examined

Blue light and violet light is everywhere these days. It used to be that people would work in an office or even out in the field minimally exposed to this essential, yet potentially harmful, color combination. It was’t until most people got home and retired from dinner to watch the evening news that blue light would penetrate their vision. Excessive violet light would come later, after intense modernization affected the environment. Now, the exposure to blue light and violet light has increased, making you more vulnerable to retinal damage which could lead to macular degeneration.

The sun is stronger due to the near depletion of the ozone layer (which is repairing itself with slow, but attainable human interference). However, the sun is hotter and ultraviolet light in nature is more prevalent along with blue light, particularly during exposure to sunlit reflections. Add in the constant use of blue light monitor devices such as cell phones, computers, tablets and televisions and this dangerous hue is front and center when it comes to potential damage to your vision.

According to the American Macular Degeneration Foundation (AMDF)

“Recent studies suggest that the blue end of the light spectrum may also contribute to retinal damage and possibly lead to AMD [age related macular degeneration]. The retina can be harmed by high-energy visible radiation of blue/violet light that penetrates the macular pigment found in the eye.”

As a result of laboratory testing on fruit flies, excessive exposure to blue light was found to be highly dangerous to humans as well. However, even though fruit flies reacted negatively to blue light exposure, the reasoning was never discovered, just the risks heeded. Now, researchers have been able to delve deeper into the effects of blue light on fruit flies and what it may mean for humans.

Purdue Agriculture reports that,

“For decades, scientists have known that blue light will make fruit flies go blind, but it wasn’t clear why. Now, a Purdue University study found how this light kills cells in the flies’ eyes – a finding that could serve as a useful model for understanding human ocular diseases such as macular degeneration.”

Oxidative Damage

Researchers found that the photoreceptor cells and optical neurons in the eyes of older flies would become overloaded when exposed to blue light. The result would be immediate blindness. However, although the blue light was damaging it turned out that when younger flies were exposed there was no reaction.

It was found that due to what is called lipid peroxidation found in older fruit flies, oxidative damage would result causing retinal damage. Lipid peroxidation occurs when system damaging free radicals take electrons from fats (aka lipids) found in cells. The oxygen is altered causing oxidative stress which results in the body being unable to initiate an oxygen species able to react to this damage. As a result, an imbalance is created in the biological system’s ability to detoxify or repair the resulting damage. This accumulated cell damage which, when occurring on the retina, creates the perfect environment for development of macular degeneration.

Cytochrome b5 to the Rescue

Reducing lipid peroxidation soon became the focus as researchers scurried for anything that would have a positive effect. It turns out that when fruit flies were fed strong antioxidants, the results showed promise.

The antioxidants began reducing the levels of lipid peroxidation due to an overexpression of a protein called cytochrome b5. This protein increases the transport of electrons to cell enzymes and begins to encourage the production of the detoxifying reactive oxygen species previously rendered unable to respond.

Researchers concluded that,

“fruit fly models can help discover how genetic therapies or drugs could slow or stop vision loss. Lipid peroxidation is believed to play an important role in the development of human retinal disease such as age-related macular degeneration,”

Antioxidant Application

Although blue light damage reversal in fruit flies is beginning stage research, other studies confirm that consuming more antioxidants could help protect your vision.

According to a Science Daily report,

“A supplement that combines antioxidants with zinc and copper is a relatively inexpensive and effective means of halting the progression of a certain type of degenerative eye disease, concludes research published online in the British Journal of Ophthalmology.”

In addition, following a high plant-based diet that consists of non-processed dark green leafy vegetables, carrots, and berries will add to your antioxidant load.

This list, as reported by Superfoodly, shows some of the highest foods on the ORAC (oxygen radical absorption capacity) scale which measures good oxygen function against free radicals:

  • Goji berries: 4,310 ORAC score
  • Wild blueberries: 9,621 ORAC score
  • Dark chocolate: 20,816 ORAC score
  • Pecans: 17,940 ORAC score
  • Artichoke (boiled): 9,416 ORAC score
  • Elderberries: 14,697 ORAC score
  • Kidney beans: 8,606 ORAC score
  • Cranberries: 9,090 ORAC score
  • Blackberries: 5,905 ORAC score
  • Cilantro: 5,141 ORAC score

The next time you see a fruit fly you may want to think twice before rolling up a magazine and swatting. These tiny buzzers have proven that they are a close friend to humans and could help save your sight someday by continuing to offer clues to help fight macular degeneration.