April 24, 2014

Learn about Stem Cells and Macular Degeneration

Amsler Grid. Cover one eye and look at the dot in the center of this grid.  Click on the image to see it in larger size. If you do not have  AMD related damage to your central vision then all the lines should look straight and parallel. If they look bent or curvy, or parts of the grid are broken or covered by dark spots, then you should go and see an eye doctor for a look at your retina

Age Related Macular Degeneration, or AMD, affects the most important vision we have. Our central vision, our detailed vision. The vision we use to read, see faces of who we are talking to, and for driving. Thus, AMD is devastating to our normal lifestyle and we really have no cures for this condition yet. AMD is a condition related to aging itself and its occurrence and progress is somewhat complicated. Environmental factors influence our risk of this disease, such as smoking. Also, there is a genetic factor for many who suffer this condition. We have found, in the last decade, that some genetic variants of several genes tend to increase the risk of AMD.

AMD is a condition where a special layer of cells in our retinas called the Retinal Pigment Epithelium (RPE) perish. These cells are important for recycling the visual chemical machinery of photoreceptor cells that detect light and start the process of our vision. Thus, once the RPE cells die, the photoreceptors adjacent to them stop working and eventually the photoreceptor cells can die as well. 

If you look at an Amsler grid and see a disrupted pattern as shown on the right-above, this may indicate that your central visual "macular" region of the retina is becoming irregular, bumpy, and damaged by the process of AMD. My advice as a vision scientist to us all: get a regular eye checkup every year if possible, certainly every two years at the least. Because the factors of both your genetics and your lifestyle contribute to AMD risk, you can reduce your risk by pursuing good general health. Do not eat lots of sugars and carbs, do eat veggies and fruits, do get exercise, do avoid becoming overweight and certainly do not smoke. Wear a brim hat or ball-cap to shade your eyes from the Sun.

Scientists are working on ways to treat AMD for patients who suffer the disease. Much of this work is funded by the National Institutes of Health in the USA, and several private funding agencies in the US, Canada, UK, Australia, Asia and the EU. With our aging demographics and increasing lifespans in the developed world, the incidence of AMD will likely affect 1/3 of us over age 60. 

One idea for treatment involves replacing RPE cells where they are lost, before your photoreceptor cells die away. One source of those cells comes from stem cell technology. When we grow mouse or human stem cells in a dish, they have to be cultured very carefully or they loose their stem cell nature and start to differentiate into specific cell types. Historically, it just so happens that many stem cells in such a dish make pigment and become very close to being RPE cells. Additional work over the last decade has refined processes to make sheets of RPE cells from stem cells. The trick then is to make sure the stem cell derived RPE cells are safe, stable (no tumor formation) and transplantable into the back of an AMD patient's eye. Unfortunately, if you have a genetic physiology that promotes the loss of RPE cells, you may then start to loose newly transplanted RPE cells.

Not sure about stem cells? Worried about moral issues surrounding stem cells? Before you fear the unknown, I recommend this 20 minute TedX talk by Dr. Dennis Clegg, UCSB, if you want to understand about stem cells and where they come from. See the link below.

Also, learn how California and Wisconsin researchers are working towards replacing lost Retinal Pigment Epithelial cells (RPE Cells) in patients going blind from AMD: age-related macular degeneration.

In vision science and eye research institutes like ours (Oakland University ERI), this is why we work to understand how our eye's biochemistry, cells and tissues work. We hope to learn enough to start to tackle once mysterious illnesses like AMD.


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