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Cognitive Decline: The Aging Human Brain

What is Aging? Alzheimer’s Disease Parkinson’s Disease. Cognitive Decline: The Aging Human Brain. What is Aging?. Denoted by the following: Declining ability to respond to stress. Increased homeostatic imbalance. Increased risk of aging-associated diseases.

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Cognitive Decline: The Aging Human Brain

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  1. What is Aging? Alzheimer’s Disease Parkinson’s Disease Cognitive Decline: The Aging Human Brain

  2. What is Aging? • Denoted by the following: • Declining ability to respond to stress. • Increased homeostatic imbalance. • Increased risk of aging-associated diseases. • Death is the ultimate consequence of aging. • Gompertz-Makeham Law of Mortality- • Mortality rate rises rapidly with age.

  3. What is Aging? • Organismal Senescence: • Process in which normal diploid cells loose their ability to divide. • Shortened telomeres (ends of chromosomes). • Causes cellular apoptosis . • Hayflick Limit: • Human- 50 cell divisions in vitro • Lobster- unlimited • Each mitosis shortens the telomeres on the DNA of the cell. • Telomere shortening in humans eventually blocks cell division and correlates with aging. • This mechanism prevents genomic instability and the development of cancer. (Carnosine can increase the Hayflick limit in humans.)

  4. What is Aging? • Why do our cells do this? • Prevents tumor cell proliferation. • Fountain of Youth: • Why is the cure for cancer much more important than treating cancer? • Polyploidy cells allow for cellular immortality.

  5. What is Aging?

  6. What is Aging? • Henrietta Lacks(HELA)

  7. The Aging Brain • Changes: • Brain and spinal cord lose nerve cells and weight. • Nerve cells transmit messages more slowly. • Waste products collect in brain tissue as nerve cells break down creating abnormal structures called plaques and tangles. • Reduced or even lost reflexes and sensation. • Slowing of thought, memory. • Senility is not a factor in aging, it is a factor caused by illness of the brain.

  8. Alzheimer’s Disease • Form of dementia that gradually gets worse over time. • Affects memory, thinking, and behavior. • Includes problems with language, decision-making, judgment, and personality.

  9. Alzheimer’s Disease • Risk Factors: • Age (not a part of normal aging). • Close blood relatives. • Certain combination of genes for proteins that appear to be abnormal in Alzheimer's. • Longstanding high blood pressure. • History of head trauma. • Female gender.

  10. Alzheimer’s Disease • Two Types: • Early Onset-Symptoms before age 60 and much less common. • Late Onset-Symptoms after age 60 and much more common. • Diagnosis: • The only way to know for certain that someone has AD is to examine a sample of their brain tissue after death. • Neurofibrillary tangles-twisted fragments of protein within nerve cells that clog up the cell. • Neuritic plaques-abnormal clusters of dead and dying nerve cells. • Senile plaques-areas where products of dying nerve cells have accumulated around protein.

  11. Alzheimer’s Disease

  12. Alzheimer’s Disease • When nerve cells (neurons) are destroyed, there is a decrease in the chemicals that help nerve cells send messages to one another (called neurotransmitters). • As a result, areas of the brain that normally work together become disconnected.

  13. Alzheimer’s Disease • Treatment: • There is no cure for AD. • The goals in treating : • Slow the progression of the disease • Manage behavior problems, confusion, sleep problems, and agitation • Modify the home environment • Medication: • Donepezil (Aricept), rivastigmine (Exelon), and galantamine (Razadyne, formerly called Reminyl) affect the level of a chemical in the brain called acetylcholine.

  14. Parkinson’s Disease • Part of the brain that controls muscle movement (midbrain and substantianigra involved). • Dopamine producing neurons. • Characterized by the accumulation of alpha-synuclein protein forming inclusions called Lewy bodies. • This can only be demonstrated in autopsy.

  15. Parkinson’s Disease • Symptoms: • Trembling of hands, arms, legs, jaw and face • Stiffness of the arms, legs and trunk • Slowness of movement • Poor balance and coordination • Symptoms will continue to get much worse.

  16. Parkinson’s Disease • Begins around age 60. • More common in men than in women. • There is no cure for Parkinson's disease. • Increased risk of PD in those living in rural environments and those exposed to pesticides. • Reduced risk in smokers.

  17. Parkinson’s Disease • Treatment: • Levodopa, dopamine agonists, and MAO-B Inhibitors (reduce symptoms). • As the disease advances the use of medication produces motor symptoms known as dyskinesias.

  18. Questions?

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