11/2- Age-Related Changes in Body Physiology Flashcards
What is Aging?
- The sum of deteriorative changes with time during post-maturational life that underlie an increasing vulnerability to challenges, thereby decreasing the ability of the organism to survive
- Aging itself does not result in disease but renders the individual more susceptible to disease
What is primary aging?
- Primary aging changes are those directly dependent on the passage of time
- It is often difficult to separate out primary aging from lifestyle, environmental, or unknown disease factors
What are some examples of primary aging?
- Menopause
- Graying of hair
- Balding in men
- Loss of muscle mass
- Atrophy of the thymus
What are measurements of aging?
- Maximum life span
- For humans this is ~ 120 yo
- No evidence of change in the past 3000 yrs
- Age-Specific Mortality Rates
- Biomarkers of Age
- Things that vary with age and are used as surrogates
- Physiologic Age
- Chronologic Age
T/F: The max lifespan over the past 2 million years has increased
True
How has the max lifespan and median lifespan changed over the “recent past”?
- Max lifespan has not changed much
- Median lifespan has dramatically increased
How did age-specific mortality rates change from 1910 to 1970?
- The slope (mortality rate vs. age) are parallel. Thus, age-specific mortality rates did not change much
- Most of the improvement is due to improved childhood and obstetric care
- Median life expectancy, however, did increase 15 yrs; BUT aging did not slow down
What are age-specific mortality rates by gender? Median life expectancy?
The age vs. mortality rates are parallel, so the “rates of aging” are the same
- The median life expectancy for women is 8 yrs > men (just not because of difference in aging rates)
What are methods to increase longevity?
- Decreasing body temperature
- May only work in cold-blooded animals
- Gene manipulations in insulin/growth hormone/IGF1/mTOR pathways
- Works in rodents in “stressor free environment”
- Big effect in worms and flies
- Caloric Restriction (to 2/3 of Ad Lib diet)
- Robust finding seems to work in almost all species; though human studies are just starting
- Human studies underway but uncontrolled
- Animal seem physiologically young
- Mechanism unknown
- AntiOxidant enzyme overexpression?
How did caloric restriction affect lifespan in rats?
- Caloric restriction increased max lifespan 33% in rats
- Female C3B10F1 mice subjected to restricted caloric intakes tarting at 1 mo of age live longer
- Caloric restriction may work in Macque Monkeys as well
- However, possibly not as well in Rhesus monkeys; they live 30-35 yrs (harder to observe)
- Caloric restriction harms as may strains of mice as it helps
- Snell dwarf mice have prolonged lifespan
T/F: decreased GH alone has been found to be adequate to prolong lifespan
True
- The survival of the little mouse is found to be about 5 yrs longer
Do small or regular-sized baseball players live longer?
The smaller ones live longer
What was found in transgenic mice with a reduced core body temperature?
Increased life span (changed gene regarding brown fat)
What are key types of studies of aging?
- Cross-Sectional: Round up every person of a given set of ages and measure variable X in them (weakness: think, in Florida would find that people are born Hispanic and die Jewish)
- Longitudinal: Measure variable X in a group of people and come back after an interval and repeat the measurement (weakness: hard to keep track of people this long)
- Cohort-Longitudinal: combination of the two
__% of the US population is expected to be > 65 yo in 2030
22% of the US population is expected to be > 65 yo in 2030
(in 2010 it was 14%)