New type of omega-3 could prevent visual decline associated Alzheimer’s and other diseases

Posted on May 9, 2023 by Dawn Kaplan

A new form of the omega-3 fatty acid docosahexaenoic acid (DHA), has been developed that is able to cross into the eye’s retina to stave off the visual declines related to Alzheimer’s, diabetes and other diseases.

The DHA found in fish oil capsules and other supplements is usually in a form called triacylglycerol (TAG) DHA. TAG-DHA has benefits in other areas of the body, however, it does not reach the eyes on account of the fact that it cannot traverse from the bloodstream into the retina. For this study, researchers created a new lysophospholipid form of DHA, or LPC-DHA. Using mice, LPC-DHA successfully increased DHA in the retina and reduced eye problems associated with Alzheimer’s-like processes.

“Dietary LPC-DHA is enormously superior to TAG-DHA in enriching retinal DHA and could be potentially beneficial for various retinopathies in patients,” said Sugasini Dhavamani, a research assistant professor in the Department of Medicine at the University of Illinois at Chicago. “This approach provides a novel therapeutic approach for the prevention or mitigation of retinal dysfunction associated with Alzheimer’s disease and diabetes.”

Dhavamani will present the research at Discover BMB, the annual meeting of the American Society for Biochemistry and Molecular Biology, March 25-28 in Seattle.

In healthy eyes, DHA is concentrated in the retina, where it helps maintain photoreceptors, the cells that convert light into signals that are sent to the brain. When there is a DHA deficiency in the retina it is usually associated with vision loss. People with Alzheimer’s disease, as well as those with diabetes, retinitis pigmentosa, age-related macular degeneration and peroxisomal disorders, frequently have abnormally low levels of retinal DHA, and as a result visual impairments are common.

While boosting DHA can help to prevent such declines, increasing retinal DHA content has been a challenge with the supplements currently available. Here’s the issue: for a dietary supplement to effectively deliver DHA to the retina, the DHA must be able to first be absorbed from the intestine into the bloodstream and then cross from the bloodstream into the retina in an amount that will be beneficial to the patient.

“Increasing the retinal DHA at clinically feasible doses has not been possible until now because of the specificity of the blood-retinal barrier that is incompatible with the specificity of the intestinal barrier,” said Dhavamani. “This study uses the novel approach of dietary LPC-DHA that overcomes both intestinal and blood-retinal barriers and improves retinal function.”

The researchers tested their LPC-DHA supplement in mice bred to exhibit processes similar to those found in early-onset Alzheimer’s disease. After six months, mice that were fed LPC-DHA daily showed a 96% improvement in retinal DHA content and preserved retinal structure and function. In contrast, TAG-DHA supplements had no effect on retinal DHA levels or function.

The results suggest that LPC-DHA supplements could help to prevent Alzheimer’s-related declines in visual function. Researchers believe this approach should also be helpful for other disorders in which DHA deficiency and vision impairment are common.

The dosage of LPC-DHA used in the study is equivalent to about 250 to 500 milligrams of omega-3 fatty acids per day in humans. Because these studies were conducted in mice, additional studies would be need to be conducted to confirm that LPC-DHA is safe and effective for use in humans.

Could following the Mediterranean diet prevent blindness?

Posted on April 28, 2019 by Dawn Kaplan

The evidence is in and it shows that a poor diet plays a big role in the development of age-related macular degeneration (AMD), a leading cause of blindness in the US. A large collaboration of researchers from the EU investigated the connection between genes and lifestyle on the development of AMD has found that people who followed a Mediterranean diet cut their risk of late-stage AMD by 41% This research expanded on previous studies and suggests that such a diet is beneficial for everyone, whether you already have the disease or are at risk of developing it.

A Mediterranean diet emphasizes eating less meat and more fish, vegetables, fruits, legumes, unrefined grains, and olive oil. Previous research had linked it to a longer lifespan and a reduced incidence of heart disease and cognitive decline. Previous studies also showed following this diet can help with certain types of AMD, but only focused on different stages of the disease.

By combining this earlier research on AMD with the latest data, a clear picture emerges: Diet has the potential to prevent a blinding disease.

AMD is a degenerative eye disease. It causes loss of central vision, which is crucial for simple everyday activities, such as the ability to see faces, drive, read, and write. It’s a leading cause of vision loss among people age 50 and older, affecting 1.8 million Americans. By 2020, that number is expected to climb to nearly 3 million.

In this study, researchers analyzed food-frequency questionnaires from nearly 5,000 people who participated in two previous investigations — the Rotterdam Study, which evaluated disease risk in people age 55 and older, and the Alienor Study, which assessed the association between eye diseases and nutritional factors in people aged 73 and older. Patients in the Rotterdam study were examined and completed food questionnaires every five years over a 21-year period, while patients in the Alienor Study were seen every two years over a 4-year period. The researchers found that those who closely followed the diet were 41% less likely to develop AMD compared with those who did not follow the diet.

They also found that none of the individual components of a Mediterranean diet on their own — fish, fruit, vegetables, etc. — lowered the risk of AMD. Rather, it was the entire pattern of eating a nutrient-rich diet that significantly reduced the risk of late AMD.

There are two kinds of AMD — dry and wet. The dry type affects about 80 to 90 percent of people with AMD. In dry AMD, small white or yellowish deposits, called drusen, form on the retina, causing it to deteriorate over time. In the wet form, blood vessels grow under the retina and leak. While there is an effective treatment available for the wet type, there is no treatment available for dry AMD.

So remember you are what you eat!

To read the original article in its entirety, click here. https://www.sciencedaily.com/releases/2018/10/181001101940.htm

Biomarkers could aid in early detection of glaucoma

Posted on April 21, 2019 by Dawn Kaplan

Researchers bred mice in which the gene PTP-Meg2 (protein tyrosine phosphatase megakaryocyte 2) was mutated. As a result, the animals suffered from chronic intraocular pressure elevation. The research team successfully demonstrated that, in their model, the intraocular pressure elevation was associated with a loss of optic nerve fibers and retinal cells. They also observed that retinal cells were unable to function properly. They further discovered glial cells and certain components of the immune system showed a reaction in the animals’ optic nerve and retina. As both aspects may be relevant for neurodegeneration, specific and early intervention into these cellular mechanisms could inhibit glaucoma.

By making use of a genetic screening, the researchers identified new potential biomarkers for glaucoma, which in the future, may facilitate early detection. As a result, it will be possible to start therapy at an earlier stage, before the optic nerve and retina are damaged. The glaucoma-mouse model may, moreover, be used to test new therapy options. So far intraocular pressure was reduced and nerve cells were retained in the mice if they were given a drug that has been used to treat human patients.

With more than 60 million patients, Glaucoma is a leading cause of blindness worldwide. In Germany alone, there are one million patients — and the estimated number of unknown cases is likely to be much higher, due to the fact that symptoms often remain undetected during the early stage of the disease. In glaucoma patients, the optic nerve and the retinal nerve cells are damaged beyond repair.

To read the original article in its entirety, click here. https://www.sciencedaily.com/releases/2018/10/181025103308.htm

AMAZING: Congenital blindness reversed in mice!

Posted on April 14, 2019 by Dawn Kaplan

Researchers funded by the National Eye Institute (NEI) have reversed congenital blindness in mice by changing supportive cells in the retina called Müller glia into rod photoreceptors. The findings advance efforts toward regenerative therapies for blinding diseases such as age-related macular degeneration and retinitis pigmentosa.

“This is the first report of scientists reprogramming Müller glia to become functional rod photoreceptors in the mammalian retina,” said Thomas N. Greenwell, Ph.D., NEI program director for retinal neuroscience. “Rods allow us to see in low light, but they may also help preserve cone photoreceptors, which are important for color vision and high visual acuity. Cones tend to die in later-stage eye diseases. If rods can be regenerated from inside the eye, this might be a strategy for treating diseases of the eye that affect photoreceptors.”

Photoreceptors are light-sensitive cells in the retina, located in the back of the eye, that signal the brain when activated. In mammals, including mice and humans, photoreceptors fail to regenerate on their own. Like most neurons, once mature they no longer divide.

Scientists have long studied the regenerative potential of Müller glia because in other species, such as zebrafish, they divide in response to injury and can turn into photoreceptors and other retinal neurons. The zebrafish can thus regain vision after severe retinal injury. In the lab, however, scientists can coax mammalian Müller glia to behave more like they do in the fish. But it requires injuring the tissue.

“From a practical standpoint, if you’re trying to regenerate the retina to restore a person’s vision, it is counterproductive to injure it first to activate the Müller glia,” said Bo Chen, Ph.D. “We wanted to see if we could program Müller glia to become rod photoreceptors in a living mouse without having to injure its retina,” said Chen, the study’s lead investigator.

In phase one of a two-phase reprogramming process Chen’s team spurred Müller glia in normal mice to divide by injecting their eyes with a gene to turn on a protein called beta-catenin. A few weeks later, in phase two, they injected the mice’s eyes with factors that encouraged the newly divided cells to develop into rod photoreceptors.

The researchers found that the newly formed rod photoreceptors looked structurally no different from real photoreceptors. Additionally, synaptic structures that allow the rods to communicate with other types of neurons within the retina had also formed. To determine whether the Müller glia-derived rod photoreceptors were functional, they tested the treatment in mice with congenital blindness, which meant that they were born without functional rod photoreceptors.

In the treated mice that were born blind, Müller glia-derived rods developed just as effectively as they had in normal mice. Functionally, they confirmed that the newly formed rods were communicating with other types of retinal neurons across synapses. Furthermore, light responses recorded from retinal ganglion cells — neurons that carry signals from photoreceptors to the brain — and measurements of brain activity confirmed that the newly-formed rods were in fact integrating in the visual pathway circuitry, from the retina to the primary visual cortex in the brain.

Chen’s lab is conducting behavioral studies to determine whether the mice have gained the ability to perform visual tasks such as a water maze task. Chen also plans to see if the technique works on cultured human retinal tissue.

This is a fascinating development and one that we will definitely be following.

To read the original article in its entirety, click here. https://www.sciencedaily.com/releases/2018/08/180815130544.htm

Eye infection in contact lens wearers due to poor hygiene can cause blindness

Posted on March 31, 2019 by Dawn Kaplan

There are reports of an outbreak of a rare but essentially preventable eye infection that can cause blindness, identified in contact lens wearers in a new study led by UCL and Moorfields Eye Hospital researchers. The research team found a threefold increase in Acanthamoeba keratitis since 2011 in South-East England.

The findings showed that reusable contact lens wearers with the eye infection were more likely to have used an ineffective contact lens solution, have contaminated their lenses with water or reported poor contact lens hygiene. “This infection is still quite rare, usually affecting 2.5 in 100,000 contact lens users per year in South East England, but it’s largely preventable. This increase in cases highlights the need for contact lens users to be aware of the risks,” said the study’s lead author, Professor John Dart (UCL Institute of Ophthalmology and Moorfields Eye Hospital NHS Foundation Trust).

Acanthamoeba keratitis is an eye disease that causes the front surface of the eye, the cornea, to become painful and inflamed, due to infection by Acanthamoeba, a cyst-forming microorganism.

The most severely affected patients (a quarter of the total) have less than 25% of vision or become blind following the disease and face prolonged treatment. Overall 25% of people affected require corneal transplants to treat the disease or restore vision.

Anyone can be infected, but research shows that contact lens users face the highest risk, due to a combination of increased exposure to infection, for reasons not fully established, as a result of contact lens wear and contamination of lens cases.

Alongside these findings, they conducted a case-control study of people who wear reusable contact lenses on a daily basis (although the disease is also associated with disposable lenses), comparing those who had a diagnosis of Acanthamoeba keratitis to those who had come in to Moorfields A&E for any other reason, from 2011 to 2014.

The case-control study included 63 people with Acanthamoeba keratitis and 213 without. They all completed a questionnaire, from which the researchers found that the risk of developing the disease was more than three times greater amongst people with poor contact lens hygiene, people who did not always wash and dry their hands before handling their lenses, those who used a lens disinfectant product containing Oxipol (now phased out by the manufacturer), and for people who wore their contacts while in swimming pools or hot tubs. Showering and face washing while wearing contact lenses are also likely to be risk factors.

Acanthamoeba is more commonly found in the UK than in other countries, likely due to higher levels found in domestic (as opposed to mains) water supplies, so that water contamination of contact lenses is of particular concern in the UK.

The researchers say the current outbreak is unlikely to be due to any one of the identified risk factors in isolation.

“People who wear reusable contact lenses need to make sure they thoroughly wash and dry their hands before handling contact lenses, and avoid wearing them while swimming, face washing or bathing. Daily disposable lenses, which eliminate the need for contact lens cases or solutions, may be safer and we are currently analysing our data to establish the risk factors for these,” said Professor Dart.

To read to original article in its entirety, click here. https://www.sciencedaily.com/releases/2018/09/180921082952.htm

A Spoonful of Vegetable Oil Helps You See Better Longer?

Posted on November 9, 2013 by Dawn Kaplan

Can vegetable oil help combat blindness? Turns out it can!

The Research Center on Aging at the Health and Social Services Centre — University Institute of Geriatrics of Sherbrooke (CSSS-IUGS), England is the home of scientists who have been studying strategies for protecting retinal pigment epithelium (RPE) cells. There is a dysfunction of the RPE cells that is found in retinopathy and age-related macular degeneration, both of which are the leading causes of blindness in elderly people in developed countries.

Findings published in the Canadian Journal of Physiology and Pharmacology suggest that incubating retinal cells with vegetable oils induces biochemical and biophysical changes in the cell membrane, which may have a beneficial effect in preventing or slowing the development of retinopathy.

The research was centered around the fluidity of the membrane in the eye. The better the fluid in and around the membrane the smoother the eye operates. When there is not enough membrane fluidity the rotation and diffusion of proteins are affected. However, an increase in the membrane fluidity enables the membrane to be more flexible and eases the transmission of light through the eye.

The researchers discovered that the fatty acids present in vegetable oil integrate in retina cells and increase the plasma membrane fluidity.

So what does all this mean? The researchers concluded that a diet low in trans-unsaturated fats and rich in omega-3 fatty acids and olive oil may reduce the risk of retinopathy. Additionally, the research suggests that replacing the neutral oil found in eye drops with oil that possesses valuable biological properties for the eye could also contribute to the prevention of retina diseases.

This adds to the already established research that what you eat has a direct impact on your health and wellness.

To read the original article, visit: https://www.sciencedaily.com/releases/2013/08/130815113644.htm

Can Your Eyes Be a Window to Your Stroke Risk?

Posted on October 18, 2013 by Dawn Kaplan

Your eyes may be a window to your soul, but could they also be a window to your stroke risk?

In a recent study detailed in the American Heart Association journal Hypertension, researchers state that retinal imaging may someday help assess if a person is more likely to develop a stroke. This could be an invaluable diagnostic discovery – strokes Eyes and Strokes are the nation’s No. 4 killer and a leading cause of disability.

“The retina provides information on the status of blood vessels in the brain,” said Mohammad Kamran Ikram, M.D., Ph.D., lead author of the study and assistant professor in the Singapore Eye Research Institute, the Department of Ophthalmology and Memory Aging & Cognition Centre, at the National University of Singapore. “Retinal imaging is a non-invasive and cheap way of examining the blood vessels of the retina.”

Globally, high blood pressure is the single most important risk factor for stroke. However, until now there has not been a reliable way to predict which high blood pressure patients are more likely to develop a stroke.

THE STUDY:

Researchers tracked stroke occurrence for an average 13 years in 2,907 patients with high blood pressure who had not previously experienced a stroke. At the baseline, each patient had photographs taken of the retina, the light-sensitive layer of cells at the back of the eyeball. Damage to the retinal blood vessels attributed to hypertension — called hypertensive retinopathy — evident on the patient photographs was scored as one of four ways: none, mild, moderate, or severe.

THE FINDINGS:

During the follow-up, 161 participants experienced a stroke: 146 caused by a blood clot and 15 by bleeding in the brain.

After adjusting for several stroke risk factors such as age, sex, race, cholesterol levels, blood sugar, body mass index, smoking and blood pressure readings, researchers found the risk of stroke was 35 percent higher in those with mild hypertensive retinopathy and 137 percent higher in those with moderate or severe hypertensive retinopathy. The researchers determined that even in patients whose blood pressure was successfully controlled by medication, the risk of a blood clot was 96 percent higher in those with mild hypertensive retinopathy and 198 percent higher in those with moderate or severe hypertensive retinopathy.

While this research opens the door for early risk detection in patients with hypertension, Ikram states “It is too early to recommend changes in clinical practice, other studies need to confirm our findings and examine whether retinal imaging can be useful in providing additional information about stroke risk in people with high blood pressure.”

More research is being done on the benefits of retinal imaging. But one thing is for sure: retinal imaging would be an inexpensive and non-invasive way to assess risk.

To read the original article, visit: https://www.sciencedaily.com/releases/2013/08/130812170207.htm