aging

Replicative senescence…

Is always detrimental to the organism

Causes uncontrolled cell proliferation

 

Is achieved when cell divisions hit Hayflick limit

Is only encountered in the process of aging

increases individual's fitness

Is achieved when cell divisions hit Hayflick limit

Cellular senescence is involved in the following EXCEPT

 

inflammation

Tumor promotion

increasing force of selection 

Tumor suppression

Aging

increasing force of selection 

Normal human cells will divide ______ times before reaching senescence or apoptosis.

More than 200

100-115

40-60

infinite number of times

Less than 15

40-60

Caloric restriction mediates its effect on a lifespan via the following mechanism

metformin

TOR pathway

increased amino acids concentration

 ncrease in Hayflick limit

DAF-16

TOR Pathway

TAME trial used metformin, which is the widely prescribed medication for

 

 

weight loss 

Type I diabetes

Gram-positive infections

Cancer

Type II diabetes

Type II diabetes

Senescent cells

Spontaneously revert to  a “young” phenotype

Are “invisible” to the immune system

harbor bacteria promoting infectious disease

Are biochemically  inert

Secrete proinflammatory mediators

Secrete proinflammatory mediators

Which statement about Senolytics is incorrect?

can be natural or synthetic 

 can be found in regular foods 

Are experimental

Are widely used in clinical practice

are found in natural products

Are widely used in clinical practice

The ____________ theory proposes: Genes that are beneficial early in life may not be later in life.

expendable soma

Evolutionary theory

Rate of living theory

Mutation theory

Antagonistic Pleiotropy theory

Antagonistic Pleiotropy theory

Insulin resistance is characterized by

Decreased sensitivity of peripheral tissues to insulin

Decreased insulin production

Generalized weight loss 

Elevated HDL (high density lipoprotein)

Increased risk of type I diabetes

Decreased sensitivity of peripheral tissues to insulin

aging

progressive decline

• age specific

senescence

occurs throughout lifespan

senescent cells

• number inc with age

• aid in wound healing

• relase pro inflamm factors

Mccay theory of caloric restriction in rats

reduction in energy rather than nutrients was responsible for increased longevity

• hoped to disprove vitamins

rats with decreased energy/nutrients = didn’t live long

restriction worked better in M

what did barton observed about yeast cells

they can die

replicative aging

number of times a cell can divide to produce a daughter

Medawar theories

father of transplantation

• discovered acquired immunity

endocrine theory

• new uses of “old” hormones

why has evolution allowed senesce

senescent cells are “old”

when an org is done reproducing what happens to it “doesn’t matter”

• selection shadow… deleterious mutation show up late in life. these mutations are not “seen” by natural selection

antagonistic pleiotropy

trade off

higher reproducitivty but shorter life span

Hayflick theory

normal human cells can divide a limited amount of times

GRIM reaper genes

AGE 1

DAF 2

Sir 2

TOR pathway

TOR= sensor for how many amino acids are available

• high amino acids = grow

what cells are “good citizens but bad neighbors”

senescent cells

Francesci theory

chronic inflammation → early death

TAME trial

metformin (T2D treatment) and placebo

M/F ages 65-90 with age released diseases

does metformin aid in age releated diseases?

Metformin in mice

makes mice life longer and look healthier

senolytics

destroy senescent cells

• ex: fisetin, curcumin

Senolytics in cancer

curcumin = induce senescence (cancer→ senescent cells)9

fisetin= destroy senescent cells

lifespan vs healthspan

lifespan= how long you live

healthspan= how long you stay healthy