Alzheimer's disease and amyloid beta | Immune system and amyloid beta

Summary

The video explains Alzheimer's disease, a brain disorder affecting millions worldwide. It delves into how the disease disrupts neuron function through the buildup of two proteins: amyloid beta and tau. These proteins damage communication between neurons, leading to cell death. The video also covers the role of the immune system, particularly microglia and astrocytes, in trying to remove these harmful proteins, but often exacerbating inflammation and further neuron damage. The speaker highlights the need for future treatments targeting both protein dysfunction and immune response to combat Alzheimer's effectively.

Takeaways

• 🧠 Alzheimer's disease affects 44 million people worldwide, with 5-6 million in the U.S., and it is a devastating disorder impacting brain function.
• 👪 The speaker has a personal connection to Alzheimer's, as it runs in their family, making them invested in explaining how the disease works.
• 🌳 Neurons in the brain have distinct parts: dendrites (which receive information), axons (which send information), and axon terminals where signals are transmitted to other neurons.
• 🔴 Alzheimer's disease involves two problematic proteins: amyloid beta and tau, which accumulate in neurons and disrupt their function.
• 🐢 Amyloid beta builds up in the neuron’s cell body, slowing down the communication between neurons, while tau tangles cause the collapse of axonal 'superhighways.'
• ⚠️ Over time, the accumulation of these proteins leads to neuron death, and neurons cannot be easily replaced, worsening cognitive decline.
• 🧬 Microglia and astrocytes, immune cells in the brain, try to clean up amyloid beta plaques but eventually contribute to inflammation, which accelerates neuron death.
• 🌡️ Chronic inflammation, potentially triggered by lifestyle factors like diet and exercise, is linked to an increased risk of developing Alzheimer's.
• 🔬 Alzheimer's progression involves both protein malfunction and immune system dysregulation, making it a complex disease with no current cure.
• 📅 Early-onset Alzheimer's (age 50-65) is more related to protein issues, while late-onset Alzheimer's (age 70-80) is likely driven by immune system dysfunction.

Q & A

What is Alzheimer's disease and how many people are affected globally?

Alzheimer's disease is a devastating disorder that affects the brain, causing memory loss and cognitive decline. Currently, 44 million people globally are living with the disease, with about 5-6 million in the United States.

What are the two main proteins involved in Alzheimer's disease?

The two main proteins involved in Alzheimer's disease are amyloid beta and tau. Both proteins become dysfunctional and contribute to the disease's progression.

How does amyloid beta affect neurons in Alzheimer's disease?

Amyloid beta is normally produced by neurons, but in Alzheimer's disease, the neuron produces too much or cannot clear it properly. This leads to amyloid beta accumulation, which slows down the neuron and disrupts its ability to send signals to other neurons.

What role does tau protein play in Alzheimer's disease?

Tau protein is involved in maintaining the structure of the axon, the part of the neuron responsible for transporting signals. In Alzheimer's disease, tau becomes dysfunctional, causing the axon's 'superhighway' to collapse, leading to disrupted communication between neurons.

What happens to the brain's neurons during Alzheimer's disease?

In Alzheimer's disease, neurons first slow down due to amyloid beta accumulation and tau tangles, and eventually die. Once neurons die, they are not replaced, leading to progressive brain degeneration.

How does the immune system respond to Alzheimer's disease?

The immune system, particularly cells like microglia and astrocytes, tries to help by clearing amyloid plaques through phagocytosis. However, over time, the immune system becomes overactive and produces inflammation, which kills even more neurons.

What are amyloid plaques, and why are they harmful?

Amyloid plaques are clumps of amyloid beta proteins that accumulate outside neurons. These plaques trigger immune responses that lead to inflammation and increased neuron death, contributing to the progression of Alzheimer's disease.

What is the synapse, and why is it important in Alzheimer's disease?

The synapse is the tiny space where neurons communicate with each other. In Alzheimer's disease, the buildup of amyloid beta and tau disrupts this communication, leading to slowed signal transmission between neurons.

What is the difference between early-onset and late-onset Alzheimer's disease?

Early-onset Alzheimer's typically occurs between the ages of 50 and 65 and is often related to genetic factors affecting protein production. Late-onset Alzheimer's, occurring between ages 70 and 80, may be more related to immune system dysfunction.

What are some lifestyle factors that may reduce the risk of Alzheimer's disease?

Exercise and a Mediterranean diet rich in healthy fats, such as those found in fish like salmon and olive oil, have been shown to reduce the risk of Alzheimer's disease by lowering inflammation and supporting brain health.