The Untold Story Of Immune Cells In The Eye

The Untold Story Of Immune Cells In The Eye

October 09, 2020

As kind of being a first in the imaging science, University of Rochester researchers tracked the interactions of microscopic immune cells in a living eye. Since these interactions were tracked without using dyes, this will be a game-changer for ophthalmology to treat retinal diseases that lead to blindness.

According to the time-lapse video shared by the University of Rochester, immune cells seem very visible moving through living retinal tissue at the back of an eye. It is seen in the video that immune cells crawl very slowly along the inside edge of a blood vessel and another cell slowly treads against the flow of blood in a vessel, fighting its way upstream.

In the video it is very visible that other immune cells leave the blood vessels and inch through the surrounding tissue, then congregate in a swarm, forming a beehive of activity.

In light of combining time-lapse video with artificial intelligence software, researchers are enabled to noninvasively image and track the interactions of translucent immune cells within live retinal tissue in animals.

The traditional method to this date focused on labeling the immune cells with dye or fluorescent agents being reinjected to image them. This was to find out whether it would change the behavior of the cells or not. Also, another approach was to remove cells and study them with a microscope in a dish.

What is the role of immune cells in inflammation?

Inflammation is one of the main reasons for most retinal eye diseases causing blindness and immune cells play an important role in the inflammation process. This happens in such a way that immune cells arrive at the affected tissue, and release compounds that recruit more immune cells. This makes changes in blood flow and all these interfere with vision and complicate the progression of the disease.

Optical coherence tomography was almost the only tool used to measure the thickness of retinal tissue at the back of the eye. In this measurement, the thickness of that tissue was thought to be a marker for how inflamed the tissue was. Although this method of measuring was useful to some extent, it wouldn’t tell how the cells structured in that tissue.

 

The Role of Adaptive Optics

Adaptive optics was first developed by space researchers so that telescopes could see more clearly through the Earth’s atmosphere. The technologies apply these techniques to the eye, making it possible to image individual retinal cells—down to individual photoreceptors in the living human retina—by looking through the pupil.

These developed techniques are not limited to modifying the light leaving the eye to obtain better pictures of the retina but also can modify the light going into the eye to achieve better vision. The developed methods are used throughout the world in Lasik procedures today.

Here are the main key cornerstones of how this technology made it possible for us to image the retina with unsurpassed resolution and moved us further down the path to the understanding of retinal disease;

  • In light of finding out a way to correct for aberrations of the eye, the researchers for the first time could visualize individual cells at the back of the eye
  • A new contrast technique ability was integrated into adaptive optics which could capture images of translucent objects such as immune cells.
  • Having time-lapsed videography fully functional to capture images of immune cell activity in the retina over periods ranging from milliseconds to months. Having an adjustable playback speed allowed the slow movements of those cells easily tracked.
  • Identifying the different kinds of immune cells captured in the images by using artificial intelligence (AI) computer code.
  • Tracking blood flow on time in real-time by using ultra-high-speed imaging of individual red blood cells to find out how it changed in response to the inflammation.

Merging expertise in immunology and cutting-edge imaging technology truly made researchers able to image the immune cells in their actual native setting. The main characteristic of immune cells is that they are mobile and extremely dynamic, rushing to wherever inflammation occurs.

More advanced key engineering advances rendering immune cell imaging and blood flow quantification in the retina. The effective use of infrared light low levels means that this approach can be safely translated to human study.

Also, the use of high-speed imaging to measure blood flow revealed surprising details about how inflammation behaves in the central nervous system. It has come out that veins and arteries achieve an increase in blood flow to the inflamed retina through markedly different ways. This finding is indeed very important for designing and testing future treatments to resolve inflammation.