Age-Related Macular Degeneration & Alzheimer’s

Similar Diseases, Different Locations, Possible Common Treatments

There are many similarities between two age-related diseases (Age-related Macular Degeneration and Alzheimer’s disease) that can affect thousands of people world-wide. In the United States there are 11 million people that have some form of AMD and it is estimated to grow to 22 million by the year 2050. Furthermore, in 2016 it was estimated that the cost to care for those with AMD was $512 billion. Worldwide it is estimated that by 2020, there will be 96 million people with AMD. National Eye Institute 

The second aging disorder that causes high degree of damage is Alzheimer’s disease. Presently, in the United States there are 5.4 million people with Alzheimer’s disease and this will increase to approximately 13.8 million by 2050. In 2016, the cost for caring for these patients was $236 billion. Worldwide the numbers of Alzheimer’s patients are estimated to be 44 million and the global cost is $605 billion. Alzheimer’s Association

Similar Risk Factors

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The risk factors for both AMD and Alzheimer’s disease are very similar to each other. These include aging, smoking, and high cholesterol. Both diseases are found more frequently in women than men and in approximately 5% to 15% the diseases are found in more than one family member. There is also a genetic risk factor of a lipid transport protein called Apolipoprotein E (ApoE) that provides elevated risk in AMD patients if they carry the allele 2 variant and higher risk in Alzheimer’s patients if they carry the allele 4 variant.

In AMD and Alzheimer’s disease there are 3 events that make the pathologies very similar except that they are found in different locations, either the retina or the brain.

1. Amyloid beta is a protein that is not present in normal tissues but larger quantities accumulate in the brain for Alzheimer’s patients and are identified to be plaques by MRI scans. The presence of these plaques is defining (pathognomonic) for Alzheimer’s disease. In AMD patients amyloid-beta deposits are found to accumulate underneath the retina and form small clumps of protein-lipid materials called drusen. This is significant because the amyloid-beta is very toxic and harmful to the surrounding cells and when it is accumulating in tissues, it causes the cells to be damaged and loss their abilities to function.

2. A second feature of both AMD and Alzheimer’s disease is that there are high levels of tissue damage, loss of function and a lot of cell death in the retina and brain.

3. Finally, both diseases have damage to the mitochondria, which are small units within the cells that are critical to keeping the cells alive. The mitochondria are the “batteries” of the cell providing energy to keep the retina and brain cells functioning. Mitochondria are similar to the batteries in a flashlight. You can have a very expensive flashlight but if you do not have good batteries, the flashlight will not work. It is a similar situation to the cell. As long as the mitochondria are healthy and providing energy the cells can function. However, when the mitochondria start to die, then the cells will lose their functions and cell death will occur. This is true for all types of cells in the body, such as nerve cells, muscle cells, retinal cells, heart cells, etc. In other words, healthy mitochondria are critical to keep cell alive and functioning well.

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Future Treatments

Using a novel in vitro model called cybrids (cytoplasmic hybrids), Dr. Cristina Kenney’s laboratory has shown that when mitochondria from patients with AMD are placed into specialized human retinal cells, the AMD mitochondria will cause the cells to die more rapidly than normal because they are so damaged. With this important discovery, the goal of the research group has been to identify drugs and proteins/peptides that can rescue the damage AMD mitochondria and protect the retinal cells. Their research is moving forward very quickly and testing drugs is the top priority for Dr. Kenney’s group. By rejuvenating the mitochondria from ‘old-damage’ to ‘new-healthy’ will prolong the health of the retinal cells and protect vision loss from AMD. What is learned in these studies will have long reaching applications to other aging-diseases such as Alzheimer’s and Parkinson’s diseases.


Source: Daily Dose of Eye Care

https://www.lvcenter4sight.com/age-related-macular-degeneration-amp-alzheimers/

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Source: Daily Dose of Eye Care

https://www.lvcenter4sight.com/call-for-surgeons-to-assist-with-premium-iol-focus-group-recruitment/

Eye Movements May Reveal Autism

autism.jpgCertain rapid eye movements of a subgroup of people on the Autism Spectrum Disorder may aid in diagnosis. The brain controls the eyes. Therefore, certain eye movement tests provide insight into the brain’s functioning.

Researchers at the University of Rochester Medical Center1 studied “saccades.” These are the rapid eye movements people make when shifting their attention from one object to another. A neurotypical person has saccades that are precise, rapid and accurate. However, certain people on the autism spectrum have noticeably different saccades.

The study required subjects to track a target on a screen visually. The targets were designed to cause the subject’s focus to overshoot the target often. Neurotypical subjects corrected their eye movements after trying the task a few times. Autistic subjects kept missing the target. This indicated impairment in the cerebellum’s sensory-motor controls that handle eye movement.

Fetal Eye Development and Autism

During fetal development, the neural plate develops two tiny dimples. These dimples develop into the retinas. Therefore, the retina is actually neural tissue. The eyes and vision are part of the central nervous system. The fetus floats in amniotic fluid. When the mother shifts position, the fetus learns a sense of balance (the vestibular system). One theory of autism is that disruptions occurred that hampered fetal vestibular development. Vision is closely linked to the sense of balance.

Abnormal Eye Movements

The abnormal eye movements in the study indicate cerebellum dysfunction. The researchers believe that they may also offer explanations for social and communication deficits in autistic individuals.

Autism is a broad spectrum of symptoms that vary widely between individuals. Therefore, treatment is not a one-size-fits-all solution. Doctors are aiming to provide very detailed diagnoses (phenotypes). Specific diagnoses could lead to more effective treatments.

The hope is that further research will lead to more treatments. Helping autistic patients improve their saccade adaptation could help heal the brain and alleviate autistic symptoms.


Source: Daily Dose of Eye Care

https://www.lvcenter4sight.com/eye-movements-may-reveal-autism/