Eyes Provide Peek at Alzheimer’s Disease Risk

Protein deposits in retina and brain appear to parallel possible neurodegeneration, an insight that might lead to easier, quicker detection. Amyloid plaques are protein deposits that collect between brain cells, hindering function and eventually leading to neuronal death. They are considered a hallmark of Alzheimer’s disease (AD), and the focus of multiple investigations designed to reduce or prevent their formation, including the nationwide A4 study.

But amyloid deposits may also occur in the retina of the eye, often in patients clinically diagnosed with AD, suggesting similar pathologies in both organs. In a small, cross-sectional study, a team of researchers, led by scientists at University of California San Diego School of Medicine, compared tests of retinal and brain amyloids in patients from the A4 study and another study (Longitudinal Evaluation of Amyloid Risk and Neurodegeneration) assessing neurodegeneration risk in persons with low levels of amyloid.

Like the proverbial “windows to the soul,” the researchers observed that the presence of retinal spots in the eyes correlated with brain scans showing higher levels of cerebral amyloid. The finding suggests that non-invasive retinal imaging may be useful as a biomarker for detecting early-stage AD risk.

Amyloid deposits tagged by curcumin fluoresce in a retinal scan.

This was a small initial dataset from the screening visit. It involved eight patients,” said senior author Robert Rissman, PhD, professor of neurosciences at UC San Diego School of Medicine. “But these findings are encouraging because they suggest it may be possible to determine the onset, spread and morphology of AD — a preclinical diagnosis — using retinal imaging, rather than more difficult and costly brain scans. We look forward to seeing the results of additional timepoint retinal scans and the impact of solanezumab (a monoclonal antibody) on retinal imaging. Unfortunately we will need to wait to see and analyze these data when the A4 trial is completed.”

The findings published in the journal Alzheimer’s & Dementia.

https://ucsdnews.ucsd.edu/

Eye Drops Reverse Vision Loss

Eye drops that can reverse poor vision? It may sound like science fiction, but one Israeli company is aiming to bring this product to market. The drops passed their Phase 2b clinical trial earlier this month, meaning they’ve proven to improve farsightedness, the inability to see or read nearby objects, and are highly tolerable.

Although results have yet to be released, Israel-based Orasis, Pharmaceuticals, revealed details last week about the latest results of the Phase 2b study for their CSF-1 eye drops. The drops offer temporary relief reversal of farsightedness. Their effects can be felt quickly, although they only last for a few hours.

The study was based on results from 166 participants across several research centers in the U.S. and designed to test both the efficacy and safety of the product. According to Elad Kedar, CEO of Orasis, results are extremely positive.

We are very encouraged by the results,” said Kedar. “The results were great not only on the efficacy endpoints, but also on the safety and tolerability, so we are moving as quickly as possible into Phase 3.”

According to Kedar, the drops are made from chemicals already existing in eye medication for other treatments. In addition, the concentrations used in the eye drops are far lower than those already used for current eye treatment. In trials, patients improved their eyesight by three eye chart lines, which is the FDA requirement for eyesight studies, according to Kedar.

Source: https://www.orasis-pharma.com/

How To Restore Sight To The Blind

For more than a decade, researchers have been working to create artificial digital retinas that can be implanted in the eye to allow the blind to see again. Many challenges stand in the way, but researchers at Stanford University may have found the key to solving one of the most vexing: heat. The artificial retina requires a very small computer chip (nanocoputer) with many metal electrodes poking out. The electrodes first record the activity of the neurons around them to create a map of cell types. This information is then used to transmit visual data from a camera to the brain. Unfortunately, the eye produces so much data during recording that the electronics get too darn hot.

The chips required to build a high-quality artificial retina would essentially fry the human tissue they are trying to interface with,” says E.J. Chichilnisky, a professor in the Neurosurgery and Ophthalmology departments, who is on Stanford’s artificial retina team.

Members of the team, including Chichilnisky and his collaborators in Stanford’s Electrical Engineering and Computer Science departments, recently announced they have devised a way to solve that problem by significantly compressing the massive amounts of visual data that all those neurons in the eye create. They discuss their advance in a study published in the IEEE Transactions on Biomedical Circuits and Systems.

To convey visual information, neurons in the retina send electrical impulses, known as spikes, to the brain. The problem is that the digital retina needs to record and decode those spikes to understand the properties of the neurons, but that generates a lot of heat in the digitization process, even with only a few hundred electrodes used in today’s prototypes. The first true digital retina will need to have tens of thousands of such electrodes, complicating the issue further. Boris Murmann, a professor of electrical engineering on the retina project, says the team found a way to extract the same level of visual understanding using less data. By better understanding which signal samples matter and which can be ignored, the team was able to reduce the amount of data that has to be processed. It’s a bit like being at a party trying to extract a single coherent conversation amid the din of a crowded room — a few voices matter a lot, but most are noise and can be ignored.

We compress the data by being more selective, ignoring the noise and baseline samples and digitizing only the unique spikes,” Murmann says. Previously, digitization and compression were done separately, leading to a lot of extra data storage and data transfer. “Our innovation inserts compression techniques into the digitization process,” says team member Subhasish Mitra, a professor of electrical engineering and of computer science. This approach retains the most useful information and is easier to implement in hardware.

Source: https://engineering.stanford.edu/

3D Printed Metamaterials With Super Optical Properties

A team of engineers at Tufts University has developed a series of 3D printed metamaterials with unique microwave or optical properties that go beyond what is possible using conventional optical or electronic materials. The fabrication methods developed by the researchers demonstrate the potential, both present and future, of 3D printing to expand the range of geometric designs and material composites that lead to devices with novel optical properties. In one case, the researchers drew inspiration from the compound eye of a moth to create a hemispherical device that can absorb electromagnetic signals from any direction at selected wavelengths.

The geometry of a moth’s eye provides inspiration for a 3D printed antenna that absorbs specific microwave frequencies from any direction

Metamaterials extend the capabilities of conventional materials in devices by making use of geometric features arranged in repeating patterns at scales smaller than the wavelengths of energy being detected or influenced. New developments in 3D printing technology are making it possible to create many more shapes and patterns of metamaterials, and at ever smaller scales. In the study, researchers at the Nano Lab at Tufts describe a hybrid fabrication approach using 3D printing, metal coating and etching to create metamaterials with complex geometries and novel functionalities for wavelengths in the microwave range. For example, they created an array of tiny mushroom shaped structures, each holding a small patterned metal resonator at the top of a stalk. This particular arrangement permits microwaves of specific frequencies to be absorbed, depending on the chosen geometry of the “mushrooms” and their spacing. Use of such metamaterials could be valuable in applications such as sensors in medical diagnosis and as antennas in telecommunications or detectors in imaging applications.

The research has been published in the journal Microsystems & Nanoengineering (Springer Nature).

Source: https://now.tufts.edu/