Alzheimer's Disease Lecture Notes

Overview

• Alzheimer's disease is a debilitating brain disorder affecting tens of millions worldwide.
• It gradually destroys memory and cognitive abilities, heavily impacting patients and families.
• Alzheimer's is responsible for 60-80% of all dementia cases.

Symptoms and Onset

• Symptoms often appear in the 60s with mild memory issues.
• Associated changes include mood shifts, increased anxiety, and difficulty coping in new situations.
• Symptoms progress over years, and eventually, patients may require constant care.

Causes and Risk Factors

• Some rare cases are due to a single inherited gene variant.
• Most cases involve multiple genes and lifestyle/environmental factors.
• The disease process starts 1-2 decades before symptoms appear, making it difficult to identify triggers.

Biological Mechanisms

• Beta-Amyloid Build-Up

  • Derived from amyloid-beta precursor protein (APP), which is crucial for neural growth and repair.
  • In Alzheimer's, APP is improperly cleaved, creating sticky beta-amyloid plaques that interfere with brain signaling.
  • Not all with plaques develop dementia, and symptom severity doesn't always correlate with plaque accumulation.

• Tau Protein

  • Normally reinforces neuron structure.
  • In Alzheimer’s, tau becomes sticky, forming toxic tangles within neurons, leading to cell death.

• Microglia and Synapse Changes

  • Changes in brain immune cells (microglia) and synapses are linked to Alzheimer's.
  • Alterations in brain energy production and consumption may also contribute.

Challenges in Treatment

• Alzheimer's is a complex cascade of events; understanding and interrupting it requires more research.

Management and Emerging Therapies

• Staying active, learning new skills, and engaging in daily activities can slow progression.
• Medications can target neurotransmitters to slow memory loss and aid learning and reasoning.
• New drugs targeting beta-amyloid demonstrate promise in slowing disease progression and reducing plaque.

Future Outlook

• Alzheimer's is not likely to disappear soon, with dementia cases expected to double in 20 years.
• Ongoing research aims at better treatments and potential prevention as the understanding of Alzheimer's evolves.