Ex3 L13 Cardiovascular Flashcards
Cardiovascular disease includes…
coronary artery disease, myocardial infarction, heart failure, stroke, cardiomyopathy, etc.
Describe the statistics on CVDs
- leading cause of death for people over 65
- approximately 25% of deaths
- coronary heart disease (CHD) accounts for half of CVD deaths
What is the greatest unmodifiable risk factor for CVD?
age
Rates of CVD are lower in women…
before menopause, because estrogen is cardioprotective
In an aged heart, we see gross changes such as…
- left ventricular hypertrophy
- diminished cardiac reserve
- degeneration of valves (especially mitral valve)
- cardiac fibrosis
In an aged heart, we see changes in cardiomyocytes such as…
- larger and flatter
- growth arrest/senescence/SASP expression
- telomere shortening
Loss of pacemaker cells with age causes…
decreased heart rate
What is atherosclerosis?
disease characterized by deposition of plaques on artery walls
Vascular aging causes…
- inflammation of arterial vessel walls
- stiffening and narrowing of arteries with age
- creates higher risk for blockage (and therefore stroke or myocardial infarction)
What role does stress play in cardiovascular disease?
- stress, anger, and depression can trigger cardiac events
- social isolation (by 1.5x)
- stress in the workplace (by 1.3x)
- stress worsens prognosis for existing CVD
How does fat distribution change with age and effect CVD?
- estrogen favors gynoid fat distribution (pear)
- cortisol favors android fat distribution (apple)
- loss of estrogen at menopause shifts fat distribution
- android has a higher risk for CVD and hypertension
How does blood pressure change with age?
- continual increase is systolic after age 30
- diastolic decreases after age 50 (increases pulse pressure due to large artery stiffness)
How does hypertension change with age?
systolic hypertension is most prevalent in ages 50+, most treatable risk factor for CVD, and treatment reduces risk of cardiac events in elderly people
What other cardiovascular changes occur with age?
- Decreased sensitivity of baroreceptors
- Increased responsiveness to SNS stimuli
- Altered renin-angiotensin-aldosterone system
How does stroke risk change with age?
- Every 45 seconds, someone in the US has a stroke
- Risk of stroke doubles every 10 years after age 55
- Strokes occur more frequently and are more severe in older people
- Death rate from stroke increases with age
What is the neurovascular unit?
- A group of cells that regulates interactions between brain tissue and
cerebral vasculature - Includes neurons, astrocytes, pericytes, microglia, epithelial cells, and vascular smooth muscle cells
What is the blood brain barrier?
- part of the neurovascular unit
- separates blood from CSF
- consists primarily of endothelial cells, pericytes, and astrocytes
How does the neurovascular unit change with age?
- decrease pericyte function (impaired regulation of blood flow, leaky BBB)
- microglia increase in number but function changes
- endothelial cells have reduced NO production and impaired vasodilation (ROS react with NO to make peroxynitrate, which damages neurons)
- all contribute to risk of ischemic stroke
How do the microglia change with age?
- increase in number but have altered function
- swtich from M2 healing to M1 inflammatory
- the more “hits” the brain experiences, the more microglia become M1 and cause neurodegeneration/inflammation and accelerating aging
How does the hormetic zone apply to the neurovascular unit?
- some inflammation and activity of microglia is necessary
- but too much (especially if it is dysregulated) can be detrimental
