Alzheimer’s Disease

For my project, I crocheted a neuron with neurofibrillary tangles. Below is a picture of my project as well as my written statement.

Introduction:

For this project, I will be talking about Alzheimer’s and relating the information to the objective “Identify the various components and key structures of the nervous system” from unit 6. My project is on Alzheimer’s Disease, how it affects the brain, and how the protein Tau plays into it. This relates back to the objective because I will discuss how Alzheimer’s Disease affects neurons and what role Tau plays in the progression of this disease. 

Alzheimer’s disease affects many of the elderly population in the United States and is considered one of the most important diseases to affect the elderly population (Hong-Qi, Y., Zhi-Kun, S., & Sheng-Di, C. 2012). Some of the general signs and symptoms of mild Alzheimer’s include memory loss, poor judgment, wandering and misplacing items in odd places. As the disease progresses, the symptoms continue to worsen, which may eventually lead to inability to communicate, no general awareness of surroundings, and even loss of normal bodily function (U.S. Department of Health and Human Services, 2022).            

What is Alzheimer’s Disease?

Alzheimer’s Disease affects the brain by disrupting the typical processes that are essential to neurons and their networks (U.S. Department of Health and Human Services, 2017). Alzheimer’s destroys neurons and their connections with other neurons, starting in the sections of the brain that are responsible for memory, the entorhinal cortex and hippocampus. As Alzheimer’s progresses, it  causes damage to the other portions of the brain, eventually leading to death. 

How does it affect the brain?

There are many different changes to the brain observed with Alzheimer’s including Amyloid plaques, Neurofibrillary tangles and Chronic inflammation. In this assignment, I will be focusing on neurofibrillary tangles. 

Neurofibrillary tangles are classified as the collection of a protein called Tau. Tau is a protein that is typically unfolded and is found in brain cells (Wang, Y., & Mandelkow, E. 2015). In a normal brain, Tau binds to microtubules to help with stability. In a brain with Alzheimer’s, Tau instead binds to other tau molecules, forming threads inside the neuron. This leads to the blockage of the neuron transport system (U.S. Department of Health and Human Services, 2017). Although functional Tau is lost to the threads and can no longer bind to microtubules, the stability of the microtubule can be compensated through the use of microtubule-associated proteins MAP1A/MAP1B and MAP2. However, a toxic form of Tau is formed which eventually leads to retrograde neurodegeneration. It is believed that it is the hyperphosphorylation of Tau that causes its loss of function and gain of toxicity (Khalid Iqbal et al. 2005). Slowly, this toxic Tau takes over the neurons and causes them to undergo retrograde degeneration. 

Current treatments:

The molecular mechanisms of the pathophysiology of Alzheimer’s disease are still unknown, which makes treatments difficult to create. Currently, the main treatments for this disease are to alleviate the symptoms rather than cure the disease. The treatments do this by attempting to appease the neurotransmitter disturbance (Khalid Iqbal et al. 2005). There are a few drugs that are in trial that focus on preventing Tau tangles and hyperphosphorylation. They appear to have influence on some Tau transgenic mice, however they have not yet been tested on humans. There are many drugs and treatments for Alzheimer’s that appear to be promising, but they are still in the early stages. 

References: 

Hong-Qi, Y., Zhi-Kun, S., & Sheng-Di, C. (2012, October 30). Current advances in the treatment of alzheimer’s disease: Focused on considerations targeting AΒ and tau – translational neurodegeneration. BioMed Central. 

Wang, Y., & Mandelkow, E. (2015, December 3). Tau in physiology and pathology. Nature News. 

Khalid Iqbal, Alejandra del C. Alonso, She Chen, M. Omar Chohan, Ezzat El-Akkad, Cheng-Xin Gong, Sabiha Khatoon, Bin Li, Fei Liu, Abdur Rahman, Hitoshi Tanimukai, Inge Grundke-Iqbal. (2005, January). Tau pathology in Alzheimer disease and other tauopathies, Biochimica et Biophysica Acta (BBA) – Molecular Basis of Disease, Volume 1739, Issues 2–3, Pages 198-210, ISSN 0925-4439,

U.S. Department of Health and Human Services. (2017). What happens to the brain in Alzheimer’s disease? National Institute on Aging. U.S. Department of Health and Human Services. (2022). What are the signs of alzheimer’s disease? National Institute on Aging. https://www.nia.nih.gov/health/what-are-signs-alzheimers-disease