Studies Flashcards
What was the effect on maximum lifespan for the intervention: exercise
Maximum lifespan increase: 15% 200 days
Mice type: Sprawg Dawley
Experiment 2018
Mice in study 22 experiment, 22 control
Control: 1064 days
Looked for and found changes in Klotho levels (higher) and reactive oxygen species (lower) in the brain and kidney
Which pharmaceutical interventions have produced the largest increase in maximum lifespan?
Which categories of interventons have demonstrated the ability to modulate aging?
- Dietary (calorie restriction)
- Behavioral (exercise)
- Genetic (IGF?, Age-1?)
- Pharmacological: Rapamycin
What is a Risk Factor
Anything that increases your odds of an adverse event occurring such as developing a condition, having an accident, or catching a disease.
How much does being 80 vs 30 increase your odds of dying, getting cancer, heart disease, or dying of a heart attack?
An 80 yr old vs a 30 yr old is:
-60x more likely to die
-30x more likely to get cancer
-50x more likely to get heart disease
Once you’re 60, how much does your odds of getting Alzheimer’s increase?
Your odds of developing Alzheimer’s doubles every five years after you turn 60.
How many chronic conditions do 65 year olds have? 80 year olds?
Half of people over 65 have two or more long term conditions
People over 80 average 5.
What percentage of deaths globally and in developed countries is aging responsible for?
Globally, aging is responsible for 2/3 of deaths.
In developed countries, aging is responsible for 90% of deaths.
What is an example of a drug simply treating the symptom rather than addressing the root cause?
Blood pressure medications work by relaxing the muscles around the arteries. But they don’t help with the stiffening of arteries or the build up of plaque, both of which are the root cause of higher blood pressure as we age.
How much would a complete cure for cancer add to life expectancy
2.5 years
How much would a complete cure for heart disease add to life expectancy
2 years
What did a US survey find regarding the average age of someone taking care of someone else over 65 and why is that important?
The average age of a caretaker for people over 65 is 63 years old. This means that we don’t see the full impact of aging until we ourselves are old.
How has life expectancy increased in the top countries since 1840?
Life expectancy in the leading country has increased by 3 months every year since 1840
High blood pressure increases your risk of a heart attack by how much? How does that compare to your risk of a heart attack by being 80 vs 40?
Having high blood pressure doubles your risk of a heart attack. Being 80 rather than 40 increases it by 10x.
What was the first body to officially recognize aging and have a coffee specifically designated for age related diseases? When did this happen?
In 2018, the WHO added a new code to the international classification of diseases: XT9T for conditions that are aging related.
What two concepts are viewed as having the largest explanatory value for why aging exists? Explain them in layman terms.
Disposable Soma hypothesis
Antagonistic pleotropy
The risk of dying before you can pass your genes on and the trade-offs that mother nature has made to allow you to pass your genes on faster. If your species has a high risk of dying from hazardous conditions, mother nature steps on the gas to get you to an age where you can be reproductive. In stepping on the gas, it makes trade-offs that favor short-term reproductive capability over long-term health. An example in humans is testosterone and prostate cancer.
Why shouldn’t we believe that evolution should favor longer lived organisms?
JBS Haldane developed an equation that shows that the force of natural selection declines with age. S(x)= l(x) • v(x) where S(x) is the force of natural selection at a given age (x) and l(x) is the probability of survival to the age of x and v(x) is the reproductive value at age x (which is equal to the expected future reproductive output.)
Define Disposable Soma hypothesis
Developed by Thomas Kirkwood in y, The disposable Soma hypothesis posits that aging occurs because there is limited time and energy that an organism has in order to successfully pass on its genes. It takes precious energy to develop robust muscles, an immune system, and other attributes. These resources could be allocated to reaching sexual maturity more quickly. So in a high hazard environment, maintaining the body is not a satisfactory trade-off vs quickly and recklessly achieving sexual maturity. Thus, aging happens faster in organisms that have higher hazards. Once the genes are passed on, the body is considered disposable.
Describe Hydra
Small centimeter long organisms that live in the water that are incredibly long lived and incredibly regenerative. Scientists calculate that 10% of them could live to a thousand years. Cut off any part of them and they can regenerate into a whole new organism.
Describe bristle cone pines in the context of longevity
The longest lived multicellular organism is a bristle cone pine somewhere in California. It is 5,000 years old. The theory is that because these grow extreme and arid places, the only way for a tree to pass on its genes is for its outlive its neighboring tree. This is a recipe for extreme longevity.
Using dietary restriction, how much has maximum lifespan been extended in various organisms?
Yeast: 300%
C elegans: 85%
Fruit flies: 66%
Mice: 65%
Mouse lemurs: 6yr normal lifespan, primate 50%
Rats: 85%
Dogs: 16%
Using dietary restriction, how much has maximum lifespan been extended in various organisms?
Yeast: 300%
C elegans: 85%
Fruit flies: 66%
Mice: 65%
Mouse lemurs: 6yr normal lifespan, primate 50%
Rats: 85%
Dogs: 16%
Explain why calorie restriction may be universal and what happens on the molecular level
Calorie restriction is important for any organism because it activates processes that increase the likelihood of survival when nutrients are scarce. Essentially, your cells sense if there is an abundance or lack of nutrients. If there’s an abundance, they store nutrients away for later. If there’s a lack of nutrients, it activates things like cellular recycling programs. Evolutionarily you wouldn’t want to reproduce during a famine because your offspring may die or you may die before you can raise them. So these processes help favor the body at the cost of the germline temporarily.
Give a brief introduction to c. Elegans
C. Elegans is a small nematode worm about a centimeter in length. A scientist named Brenner in England in the 1950s was looking for a model organism that could help in the study of neurobiology. See elegans turned out to be a great organism as they only have about 1,000 cells in them. At this point, scientists have mapped out the development of c. Elegans with incredible precision.
Explain The discovery and significance of the C. elegans genes associated with longevity.
One scientist doing lifespan studies with c. Elegans had studied 8,000 genetic variants and only found eight that had longer lives. The majority of which were simply because they had lost the ability to sense nutrients around them and so essentially were calorie restricted, so the scientist gave up.
His work was taken up by another scientist who discovered the age-1 gene, which extends lifespan by 50%. He proved this was a single Gene mutation by doing a hybrid cross experiment with its offspring. Later work by Cynthia Kenyon uncovered the daf-2 gene, which extends lifespan by 100%.
The significance is that a lifespan was shown to not be something unbelievably complex but could be influenced by a single thing. Who was also shown that new techniques related to genetics could give scientists the tools to actually do something about it.
