What is Alzheimer’s Disease?
Alzheimer’s Disease is a brain disorder that wreaks havoc with stored memories, hinders new learning, and tampers with cognitive skills.
While getting older is a natural event, Alzheimer’s Disease is not.
The communication network in the brain is composed of a maddeningly complex system of nerve cells called neurons. Picture a map with cities scattered throughout the state connected by millions of highways and back roads. These information highways are called axons and dendrites, and they carry information signals, chemicals, and electrical charges. Between the reaching fingers of dendrites are gaps called synapses.
When Alzheimer’s Disease develops, the synapses become cluttered with a protein plaque called Beta-amyloid. Picture your brain as a system of roadways. Major highways crisscross all over the place, and little country lanes intersect them all, leading in millions of directions. And just like many roads in the summertime, there are gaps here and there where information deliverers cannot leap the “bridge out” signs to connect with the next section of the road. Information can’t get through.
If you’re lucky, there is a short detour around the “road closed” sign. A brain with many connections and alternate pathways may be able to compensate for the obstructed gap. If you’re not lucky, you realize the detour is not worth the extra time, so you turn around and go home. Neurotransmitters in the brain drop the information being processed. Sometimes this information is a memory, a previously learned skill, or a decision. Whatever is being carried across the brain’s highways, the message never gets through.
Another road rage villain is a type of protein called tau that forms inside neuron cells. In healthy brains, tau attaches to microtubules to direct nutrients to the proper location. In unhealthy brains, tau attaches to other tau proteins and creates a cobweb of threads called neurofibrillary tangles blocking the transfer of information. Picture the kid on a dirt bike charging straight into the yellow construction tape and spinning circles until no one can move or escape. The construction and the clean-up processes come to a halt. The brain is unable to clear away the debris, and the road is closed forever.
Other factors may contribute to the Alzheimered mind: vascular issues where veins cannot supply enough nutrients and blood to a functioning brain, a glucose supply problem that lacks enough gas to power brain activities, inflammation that keeps cells from clearing away the clutter, brain shrinkage in the hippocampus that holds memory and the ability to learn.
Somehow all this works together (or doesn’t work together!) to allow memory and critical thinking to figure out if Auntie Nora is my second cousin on my mother’s side or my father’s side. In the tangles and barricades of Alzheimer’s, there’s just no road that takes me there anymore, and Nora is lost in a maze.
Since more than six million Americans suffer from the disease and longer life spans increase the risk of Alzheimer’s Disease, researchers and scientists are working to attack the problem in three areas. Many medicines work to relieve the symptoms of Alzheimer’s Disease – reduce inflammation, increase memory, or improve the vascular system. Some work is being done to prevent the formation of amyloid plaque and neurofibrillary tangles. Other clinical trials and research focus on undoing the roadway clutter to clear away plaque and tangles.
An early medication called aducanumab (Aduhelm) was approved in 2021 but came at a cost of over $50,000 a year. This drug probably has the longest history of Alzheimer-related use, but clinical trials show mixed results. An IV-injected medicine called lecanemab, currently priced at $26,000 a year, was approved in January 2023. While this drug comes with the possible side effects of swelling and bleeding in the brain, trials showed a reduction of amyloid plague and an improvement in memory. A new drug called donanedab is expected to go into clinical trials this year.
While drug and insurance companies hash out the “Who pays for this?” question, promising drugs are slowly making their way to those who need them. A new protocol for collaboration between government entities, researchers, funders, and pharmacies is speeding the process of clinical trials and FDA approval. New and better medicines may be available to Alzheimer’s Disease patients in the near future.
I hope so because I haven’t found a way to reduce the number of candles on my cake, no matter how creative I become in counting birthdays. Worse yet—I can’t prove I didn’t put the stack of mail in the refrigerator! Blast those “bridge out” signs!
To learn more, check out these websites:
Alzheimer’s Association – https://www.alz.org/alzheimers-dementia/treatments/medications-for-memory#Types%20of%20drugs
Duke University – https://www.dukehealth.org/blog/what-you-need-know-about-aducanumab
The Lancet – Scheltens, P., De Strooper, B., Kivipelto, M., Holstege, H., Chételat, G., Teunissen, C. E., Cummings, J., & van der Flier, W. M. (2021). Alzheimer’s disease. The Lancet, 397(10284), 1577-1590. https://doi.org/10.1016/S0140-6736(20)32205-4
National Institute on Aging – https://www.nia.nih.gov/health/alzheimers-disease-fact-sheet#changes U.S. Department of Health & Human Services – https://www.alzheimers.gov/