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Aging, Cancer, Entropy
Penelope Gourgourinion 30 May 2013
Transcript of Aging, Cancer, Entropy
telomeres shorten at each cell division! Biological theories of aging what else leads to aging?? ENTROPY = DEATH! Thermodynamically we are starting up as low entropy- high order systems that change to highly disordered ones...letting energy become HEAT! The paradox: that even though cancer is age-related, the factors that cause it seem to slow down with age!! Lifespan, cancer and energetics Wait a minute ! The same happens with cancer! Is cancer related to aging mechanisms?
Is this reversible?? pine trees live up to 4000 yrs
a fly lives for 1 day
a flea...30 days
a rat ...4 yrs
elephants... 80 yrs
great tortoises...150 yrs! p53...the champion! Low metabolic rate and prolonged lifespan is observed to organisms that have a healthy p 53 gene AND are able to withstand oxidative and metabolic stress. This gene plays major role as tumour suppresor Telomeres are made of repeating sequences of TTAGGG on one strand We have 8000 base pairs in our telomeres at birth...3000 b.p. as we grow...1500 b.p. when we get old...we lose 30 to 200 b.p. every time a cell divides!! People of the same age with longer telomeres will live at least 5 years more! what stops the destruction of telomeres is the enzyme ...telomerase Telomerase makes cancer cells "immortal"..if we fight it we kill cancer cells...but also impair immune system and wound healing!!! Dyskeratosis makes people lose telomeres faster so they suffer from prermature aging and death... leukemia..cirrhosis...hair loss.etc. OK! Telomeres...accumulation of non-repaired damages...systems are not reliable anymore...mutations...autoimmunity...clock theory...what else? Chronological age and gender combined...sorry but women live longer (!)...may account for 37% of aging! Major factor is "oxidative stress"! It is the damage to DNA, proteins and lipids caused by oxidants, which are highly reactive substances containing oxygen. These oxidants are produced normally when we breathe, and also result from inflammation, infection and consumption of alcohol and cigarettes. Also called...free radicals! all in all... stems cells stem cells and progenitor cells undergo damages that may lead to either apoptosis...senescence...or cancer.
More and more proliferative cells leave the "pool"
smaller number of stem cells remain... leading to low tissue homeostasis an degenerative capacity What hinders the entropic change is the strength of chemical bonds. Natural selection favoured structures that maintain fidelity until reproductive age The entropic change of biomolecules renders them inactive or malfunctioning BMR...speaks! Patients with cancer or cardiovascular diseases are..hypermetabolic Smokers have extremely high BMR leading to tear and wear and shorter lifespan Vegeterians have a lot higher metabolic rate than non vegetarians to reverse the process you need to provide low entropy-this is what regenerative mechanisms do otherwise your internal energy will become so useless you will not be able to use it to produce work A new born baby's system entropy will fail in 75-80 years Mitochondrial mutations and disease account for that...they follow the 2d law of thermodynamics Organisms that are..."immortal" http://www.huffingtonpost.com/2013/03/13/science-of-aging-video-biology_n_2861168.html These are marine organisms that reproduce asexually by somatic cloning These creatures have a very active telomerase. Sea squirts and long lived people share this!! i) a peak in early childhood
ii) low rate in youth
iii) increase in this rate afterwards
iv) the deceleration or decline in the rate at old ages The activity of p53 suppresses tumours but accelerates aging!