Aging and Potential Interventions
to Expand Lifespan
Ryan Shelton, ND
Longevity Project
• Continually involved, productive, engaged
in challenging interesting work (even in
stress)
• Being prudent, conscientious, intentional
• Being socially involved and helping others
• Marriage for men
Biomarkers of Longevity in
Primates
• Temperature
• Insulin
• % of initial DHEA
• Calorie restriction
– 6 mos, 48 humans VLCD reduced fasting
insulin, body temperature, DNA fragmentation
Definitions of aging
• Accumulation of changes over time
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– Manifests as decline in functional and responsive capacity
Universal aging/Probabilistic aging
Proximal aging/Distal aging
Cellular senescence/Organismal senescence
– Time of cell life vs # of cellular divisions
– Not known how cellular senescence plays a role in
organismal senescence
Biological immortality
– Stable rate of mortality as a function of chronological age
– Death requires injury or disease rather than deterioration
– Not an unavoidable property of life, rather part of the
genetic program
Biogerontology (Biomedical gerontology)
Theories of aging
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Most evidence is correlative, not causative; all are limited
Telomere shortening
Reproductive hormone theory
Damage/Error accumulation to genetic or epigenetic
factors
– Free radical theory
– Infections and inflammation
– Micro-nutrient triage
Mis-repair theory
Mitohormesis
AGE cross linkage
Evolutionary
Loss of circadian rhythms
Law of entropy
Accelerated aging diseases
• Progeria
– Genetic mutation causing unstable Lamin A, part of the building
block of the nuclear envelope/scaffolding
– Similar nuclear blebbing, nuclear receptor down-regulation and
DNA damage, poor DNA repair seen in the elderly
– Patients do not show neurodegeneration or cancer predisposition
– “Wear and tear” effects of aging not seen
• Cataracts, osteoarthritis
• Segmental progerias
– Dyskeratosis cogenita
• Poor telomere maintenance
• DNA helicase mutations
– Werner syndrome
• Increased telomere attrition
• DNA helicase mutations
Hayflick Limit
• The number of times a cell population will divide
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before it stops (Replicative senenscence)
Human cells around 50-60 divisions
– 70 divisions at physiological O2 conditions
– Tortoise 100 divisions, Mice 15
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May have been selected to prevent cancer
Only sometimes correlates with telomere length
Does not address G0 phase of cell cycle
In vivo Hayflick Limit does not hold
Apoptosis
• Programmed cell
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death
60 billion cells in
human adult, 30
billion cells in child
Apoptosis,
senescence,
quiescence
Atrophic factors
– Diminished
innervation, blood
supply, nutrition,
endocrine
stimulation; toxins,
infections. senility
Autophagy
• Degradation of intracellular proteins, organelles,
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membranes as mechanism of repair
maintenance
Taking out the trash or recycling
Stimulated by nutrient deficiency or hypoxia
Slows with age
Increase in autophagy associated with longer life
span in worms, flies, and mice
Important Genes/Enzymes
• Sirtuin family
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– NAD+ dependent protein deacetylase enzyme
– Regulates metabolism, transcription, stress resistance
– Tighter packing of chromatin, silencing most prominent at telomeric and rDNA
sequences; prevents early cell division, preserves replication
– Overexpression 30% increase in lifespan, deletion 50% decrease lifespan and
eliminates life extension of calorie restriction
– Stimulates autophagy, decreases mating factors, telomere maintenance
– Attenuates NF-kb signaling
mTOR enzyme
– Regulates cell growth, proliferation, autophagy
– Decreased TOR activity slows aging
– Decrease mitogenic signaling, immunosuppressant, cancer Tx
Daf-2, Daf-16 (Forkhead/FOXO)
– Insulin/IGF-1 like receptor genes
– Decrease signaling increases life-span analogous to calorie restriction
– Repression in early life important for later life
Telomerase
– Only expressed in stem cells, germ cells, certain WBCs
– Increased life span, concern with cancer
AMP Kinase
Matrix Metalloproteinases
RAGE
– Activate NF-kb, PRO-inflammatory
– Receptor for AGE
Important Genes/Enzymes
• HIGHLY CONSERVED ENZYMES
• Sirt, DAF, TOR AMP kinases each shift away from growth
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and reproduction towards protection and maintenance
VIA DIFFERENT PATHWAYS
PEPCK-C
– Overexpression 50% life extension in mice
• PPAR receptor
– Deletion 30% life extension in mice
• PGC-1 alpha
– Master integrator of external stimuli
• P53
– Guardian of genome repair mechanisms
– ‘Tumor suppressor gene’
– Longer life vs cancer
Telomere
Telomere Theory
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Protective ends of DNA, disposable buffers
Biological clock or fuse
Repetitive sequence, does not code for protein
Necessarily shortened with each cell mitotic division
Centenarians have longer telomeres
Psychological stress negatively correlated with telomere length and
telomerase activity; pessimism decreases WBC telomere length
Shortened telomeres associated with a wide range of degenerative diseases
– Age, smokers, insulin, coronary artery calcium & atherosclerotic plaques
• Telomeres highly susceptible to oxidative stress and are impacted more by
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this than the end-replication problem
Does not address G0 cell phase
Mice lacking telomerase do not show decreased lifespan
Increase life span in mice seen only if genetically resistant to cancer
Aged stem cells have decreased functional capacity and less functional
lineages
Reproductive hormone theory
• Reproductive hormones may act in an antagonistic pleiotropic
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manner via cell cycle signaling
Promotes growth and development early in life to achieve
reproduction
– Longer time to reproduce, longer life span
– Removal germline stem cells doubles lifespan
• Decline and desynchronization drive senescence
• Young ovaries in old rats increases lifespan
• Longevity interventions decrease fertility by decreasing HPG
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axis
HPG hormones affect longevity regulating pathways
More telomerase activity with estrogen, testosterone, DHEA
Mice w/o pituitary gland on HRT lived longer than controls
Hypothalamus and pituitary maintain capacity, end glands do
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Incomplete theory
Damage/Error accumulation
• Viruses
Damage/Error Accumulation
• 10,000 to one million lesions per cell per day
• Can alter/eliminate transcription
• Damage vs mutation
– DNA damage special problem in slow or non-dividing cells: Aging
– DNA damage in fast dividing cells can cause mutation: death of
cell or cancer
• Genes influential on lifespan involved in DNA repair
• nDNA & mDNA
• Epigenetics
– Non-genetic mechanisms of temporal and spatial genetic control
– Methyl groups, histone tails, chromatin remodeling
– Morphogens give cells memories by governing tissue
development
Mis-repair Theory
• Mis-repair was selected for as a survival
advantage
• Quick repair increases survival chances to
reproduction
• Mis-repair accumulates over time
• Distorted gene products less than optimal
function
• Aging is the price of survival
Mitohormesis
• Energy centers produce free radicals
• Induction of stress resistance through
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mitochondrial anti-oxidants
With calorie restriction, there are more antioxidants than free radicals
Anti-oxidant supplementation can downregulate
this phenom to increase morbitity/mortality
Loss of redox control progresses cell cycle from
G0 to proliferation or apoptosis
Aging associated with less anti-oxidant capacity
DNA Damage/Error
AGE cross-linkage
• Cooking ourselves to death
– Reduces elasticity (1st known effects of aging)
• Externally, a non-enzymatic reaction between an amino acid and a
reducing sugar (browning reaction)
• Internally, Advanced Glycation Endproducts undergo Amadori
rearrangements to form ketosamines on nucleic acids, proteins, and
lipids
– Form azomethine bonds
– Increased by oxidative stress, inflammation, hyperglycemia, fructose
intake
– Implicated in DM, CVD, Alzheimer’s, asthma, arthritis, nephropathy,
retinopathy, neuropathy
– Cross-linking can effect membrane fluidity/transport, cell/cell
communication, DNA damage, elasticity
– Interaction between AGE and RAGE highly pro-inflammatory and NF-kb
upregulates more RAGE expression
– AGE induces Matrix Metalloproteases
Evolutionary
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Aging is relatively new phenomenon
Little selection pressure in old age
Detrimental mutations more likely to show up later in life
Regulation of genetic expression program controlled by
activating different genes at different times or growth,
development, and day-today life
Reproduction is king; lean years when reproduction was less
likely the growth and reproductive genes turned off in favor of
protection and maintenance for a future opportunity
Exceptions to the rule
– Naked mole rat
– Turtles
– Hydras, Tardigrades
– Bristlecone pines
– Sturgeon, rockfish, lobsters, clam
– Bowhead whale
Possible interventions
• From Gilgamesh to $50bill/yr
• Most research has been in vitro and non-
mammal in vivo studies
• Best chances for drastic expansions in life
span likely with nanomedicine, gene
therapies, stem cell therapies
– Catalase gene therapy into mitochondria
increase lifespan by 25% in mice
Possible interventions
• Sleep (optimal) and maybe napping
• Diet
– Whey protein
– Neolithic
• No grain, dairy, processed foods
– Fructose and sucrose
– Calorie restriction
• Intermittent longer increase (50%) than constant restriction (30%)
• 30-50% less than ad libitum
• Methionine restriction also works
• Exercise
– Moderate, not excessive, and must be enjoyed
Telomerase
• Cancer and telomerase; p53 & Sirtuin?
• Studies in mice show rejuvenation of aged tissue
• Telomerase decrease
– Psychological stress
– Oxidative stress
– Caution with plant polyphenols?
• Telomerase increase
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Estradiol
Tamoxifen
Pioglitazone (Actos)
GHRH antagonist
Erythropoietin
TA-65 (Astragalus extract)
Terminalia chebula
Portulaca oleracea
Cistanche
Colostrum (Epidermal growth factor)
Melatonin
Reduction of IL-6
Sirtuin
• Are hypothalamic Sirt enzymes most important?
• Pharmacological mimicking of calorie restriction elicits epigenetic
reprogramming of differentiated cells to more pluripotent selfrenewal states
• Resveratrol, Piceatannol
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– SRT 1460, SRT 2183, SRT 1720
Pterostilbene
Orsirtine GL
Fisetin, Butein
Stabilized oxaloacetate
– Also may work on FOXO & AMP kinase pathways through increasing
NAD+/NADH ratio
• Melatonin
– Also reduces body temp
TOR enzyme
• Inhibited by
– Reduced calorie intake
– Caffeine
– Rapamycin
– Curcumin
– EGCG
– Resveratrol
AGE Blockade
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L-Carnosine
Benfotiamine
Aminoguanidine, Metformin
Butein, Cinnamon, clove, cherry blossom flowers,
Terminalia, red yeast rice, grape seed extract, Sophora,
Withania, Zea
Adiponectin
Genistein, ECGC
Phloridzin, phloretin
Alagebrium
Acetylsalicylic acid
Random mechanisms
• Berberine (reduce MMP)
• 2-deoxyglucose mimics calorie restriction
• Methylators are generally gene silencers
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– 5-THF, TMG, MethylB12, B6
Selegiline
– Increase SOD?
Non-TOR induced autophagy
– Clonidine, verapamil, spermidine, minoxidil
Chinese herbs
– Fo-Ti, Lycium, Panax, Rehmannia
Mitochondrial antioxidants
– Alpha lipoic acid
– Acetyl-L-carnitine
– N-acetylcysteine
• GGT-knockout mice develop cataracts in 3 weeks, die in 12 weeks
– Taurine
– SkQ
– CoQ10
– Tempol
– Catalpol
– MitoQ, MitoE
• Alkylated triphenylphosphonium to CoQ10 & Vit E
Unknown mechanisms for mice
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Vit D
B5
Aged garlic
DHEA
Ganodermasides, Cordyceps
Nucleic acids
Curcumin
Metformin
– Especially females, early treatment
BHRT
• Optimize bio-identical hormones
• Consider DHEA
• HRT patients still age
• Circadian pulsatility may be important
– SIRT1 actually involved in circadian rhythms
• GH, IGF-1 may decrease life span
Important concerns
• Cell immortality induces oncogenes or lose tumor
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suppressor genes
Life span extension verses quality improvement and
disease reduction; Optimize natural longevity
Aging is variable, aging accumulates with age
No proven method in humans of life span expansion;
medical focus is on prevention and early detection of
disease
As a system advances through time, it will statistically
become more disordered and living systems decrease
their entropy by expenditure of energy at the expense at
the expense of environmental entropy increase
For every measurable value, the variation in the
distribution in values increases with age
Can GGT be a marker for disease, oxidative stress, and
aging?
Cool Database: http://human.ageing-map.org/