1

ALZHEIMER’S ALZHEIMER’S DISEASEDISEASE

Treatment and Treatment and PreventionPrevention

Ben BestBen Best

President/CEOPresident/CEO

Cryonics InstituteCryonics Institute

2

What is Alzheimer’s What is Alzheimer’s Disease (AD)?Disease (AD)?

Only confirmed on autopsyOnly confirmed on autopsy Characterized by Characterized by

Amyloid plaqueAmyloid plaque Neurofibrillary tanglesNeurofibrillary tangles Neuronal lossNeuronal loss Synapse lossSynapse loss Inflammation and oxidative damageInflammation and oxidative damage

Tangles without plaque is FrontoTemporal Tangles without plaque is FrontoTemporal DementiaDementia

3

Empirical versus Empirical versus MechanisticMechanistic

Empirical treatment and preventionEmpirical treatment and prevention What appears to workWhat appears to work

Mechanistic treatment and preventionMechanistic treatment and prevention Understand the mechanismsUnderstand the mechanisms Devise strategies based on mechanismsDevise strategies based on mechanisms Evaluate what may work or not to Evaluate what may work or not to

understand the mechanisms and improve understand the mechanisms and improve strategies. strategies.

4

Amyloid Cascade Amyloid Cascade Hypothesis Hypothesis

Amyloid peptide Amyloid peptide Called Called AßAß (amyloid beta) (amyloid beta) Because aggregates in Because aggregates in ß (beta) sheets ß (beta) sheets

Simplified viewSimplified view      AßAß formation formation ⇒ ⇒ amyloid plaques amyloid plaques  ⇒ ⇒ neuron death neuron death  ⇒ ⇒ dementia dementia

5

Amyloid cascade begins Amyloid cascade begins APP (Amyloid Precursor Protein)APP (Amyloid Precursor Protein)

Cleaved by secretase enzymesCleaved by secretase enzymes Cleavage of APP forms shorter peptidesCleavage of APP forms shorter peptides Cleavage by alpha or beta secretaseCleavage by alpha or beta secretase Only cleavage by beta secretase forms Only cleavage by beta secretase forms

AßAß Two forms of Aß Two forms of Aß

After cleavage by gamma-secretaseAfter cleavage by gamma-secretase 40 amino acid amyloid beta peptide (Aß40 amino acid amyloid beta peptide (Aß4040)) OROR 42 amino acid amyloid beta peptide (Aß42 amino acid amyloid beta peptide (Aß4242))

STICKY!STICKY!⇒ ⇒ amyloid plaques amyloid plaques 

6

Amyloid cascade beginsAmyloid cascade begins

7

Damaging effects of AßDamaging effects of Aß4242

Activation of microglia Activation of microglia Brain version of macrophagesBrain version of macrophages Produce inflammatory cytokinesProduce inflammatory cytokines

InterLeukin-1ßInterLeukin-1ß ( (IL-1ßIL-1ß) ) Tumor Necrosis Factor alphaTumor Necrosis Factor alpha ( (TNF−αTNF−α)) Generate peroxynitrite and oxidative stressGenerate peroxynitrite and oxidative stress

Hyperphosphorylation of tauHyperphosphorylation of tau Tau protein stablizes cell microtubulesTau protein stablizes cell microtubules Phosphorylated tau forms NFTsPhosphorylated tau forms NFTs

NeuroFibrillary TanglesNeuroFibrillary Tangles

8

Damaging effects of NFTsDamaging effects of NFTs

Amyloid plaque does not cause Amyloid plaque does not cause neuron deathneuron death

NFTs are always associated with neuron NFTs are always associated with neuron deathdeath

Without microtubules neurons cannot Without microtubules neurons cannot functionfunction

NFTs become glycatedNFTs become glycated Intimately associated with AGEs (Advanced Intimately associated with AGEs (Advanced

Glycation End-products)Glycation End-products) Generate free radicals contributing to Generate free radicals contributing to

neurodegenerationneurodegeneration

9

Damaging forms of AßDamaging forms of Aß4242

AßAß42 42 is a 42-amino acid monomeris a 42-amino acid monomer AßAß42 42 monomers can aggregate intomonomers can aggregate into

Oligomers (many monomers)Oligomers (many monomers) Fibrils which can aggregate into plaquesFibrils which can aggregate into plaques

Soluble oligomers are the most toxic form Soluble oligomers are the most toxic form of Aßof Aß4242

““Halos” of Halos” of AßAß42 42 oligomers around oligomers around plaques damage or destroy synapsesplaques damage or destroy synapses PNAS;Koffie,RM;106:4012 (2009)PNAS;Koffie,RM;106:4012 (2009) JOURNAL OF NEUROSCIENCE; JOURNAL OF NEUROSCIENCE;

Lacor,PN;27:796(2007)Lacor,PN;27:796(2007)

10

Amyloid Amyloid aggregation/disaggregationaggregation/disaggregation

11

Amyloid Cascade Amyloid Cascade HypothesisHypothesis

APP ⇒ AßAPP ⇒ Aß4242  (peptide, monomer)  (peptide, monomer)

⇒ ⇒ fibrillar Aß or oligomers fibrillar Aß or oligomers 

⇒ ⇒ amyloid plaques amyloid plaques 

⇒ ⇒ inflammation/NFTsinflammation/NFTs

 ⇒  ⇒ neuron death / synapse lossneuron death / synapse loss

12

Amyloid Cascade EvidenceAmyloid Cascade Evidence Genetic pre-disposition to ADGenetic pre-disposition to AD

Onset at an early ageOnset at an early age Most often increases gamma-Most often increases gamma-

secretase cleavagesecretase cleavage Produces increased Produces increased AßAß4242   Down’s Syndrome victims produce more Down’s Syndrome victims produce more

APP APP 3 chromosomes with gene for APP3 chromosomes with gene for APP Cleaved to AßCleaved to Aß4242   Early ADEarly AD

13

Discussion Discussion

Choose a partnerChoose a partner Tell your partner what you Tell your partner what you

understood and think while your understood and think while your partner silently listens – talk for a partner silently listens – talk for a couple of minutescouple of minutes

Switch roles – partner that listened Switch roles – partner that listened becomes the speaker for a couple of becomes the speaker for a couple of minutesminutes

Short discussion Short discussion

14

Amyloid and NFTs in ADAmyloid and NFTs in AD

15

Cholesterol and the amyloid Cholesterol and the amyloid cascadecascade Human brain high in myelin to facilitate axon Human brain high in myelin to facilitate axon

conduction speed conduction speed Myelin produced by oligodendrocytes (glia)Myelin produced by oligodendrocytes (glia) Brain contains 25% of body’s membrane Brain contains 25% of body’s membrane

cholesterolcholesterol 80% of brain cholesterol is in myelin80% of brain cholesterol is in myelin

Cholesterol allows tight membrane packing in Cholesterol allows tight membrane packing in myelinmyelin

Cholesterol recycling and transport depends on Cholesterol recycling and transport depends on APOlipoprotein E (APOE)APOlipoprotein E (APOE)

16

APOE and ADAPOE and AD APOE exists in 3 allelesAPOE exists in 3 alleles

APOE2, APOE3 and APOE4APOE2, APOE3 and APOE4 APOE4 is the only allele in non-human primatesAPOE4 is the only allele in non-human primates APOE4 is less efficient than APOE3 in transporting APOE4 is less efficient than APOE3 in transporting

cholesterol and clearing the brain of cholesterol and clearing the brain of AßAß APOE3 is less efficient than APOE2APOE3 is less efficient than APOE2 14% of Caucasians have one APOE4 allele, but 40% of 14% of Caucasians have one APOE4 allele, but 40% of

AD victims have at least one APOE4 alleleAD victims have at least one APOE4 allele AßAß4242 rises markedly after head injury rises markedly after head injury Risk of AD increases many times with head injury, but Risk of AD increases many times with head injury, but

increases much more so for those with APOE4increases much more so for those with APOE4 APOE4 less efficient at myelin repair and AßAPOE4 less efficient at myelin repair and Aß42 42 clearance clearance

after injuryafter injury

17

Metal toxicity and ADMetal toxicity and AD Role of aluminum is controversialRole of aluminum is controversial Zinc, copper and iron cause Aß aggregationZinc, copper and iron cause Aß aggregation Copper particularly mediates Aß toxicityCopper particularly mediates Aß toxicity Aß is not toxic in the absence of CuAß is not toxic in the absence of Cu2+2+

Zinc inhibits Aß toxicityZinc inhibits Aß toxicity Copper enhances Aß fibril formation, an Copper enhances Aß fibril formation, an

effect potentiated by APOE4effect potentiated by APOE4 Copper is a greater catalyst for free radicals Copper is a greater catalyst for free radicals

than the other metalsthan the other metals Aß binds to both copper and cholesterol Aß binds to both copper and cholesterol

causing oxidation of cholesterol to causing oxidation of cholesterol to compounds that are extremely toxic to compounds that are extremely toxic to neuronsneurons

18

Clioquinol therapy for ADClioquinol therapy for AD Clioquinol binds zinc & copper (chelator)Clioquinol binds zinc & copper (chelator) Crosses the blood-brain barrier (BBB)Crosses the blood-brain barrier (BBB) Transgenic AD-prone mice treated with clioquinol Transgenic AD-prone mice treated with clioquinol

showed a 49% decrease in Aßshowed a 49% decrease in Aß AD patients treated with clioquinol for 12 weeksAD patients treated with clioquinol for 12 weeks

Severely demented showed slowed cognitive Severely demented showed slowed cognitive declinedecline

Moderately demented showed no effectModerately demented showed no effect ARCHIVES OF NEUROLOGY;Richie,CW;60:1685 (2003)ARCHIVES OF NEUROLOGY;Richie,CW;60:1685 (2003)

PBT2 is a clioquinol analog that has greater BBB PBT2 is a clioquinol analog that has greater BBB permeability, and more effectively strips copper permeability, and more effectively strips copper from Aß, without chelation, which could remove from Aß, without chelation, which could remove essential metalsessential metals No adverse effects seenNo adverse effects seen Currently in clinical trialsCurrently in clinical trials

19

Copper in the dietCopper in the diet Diets high in copper and saturated fats are Diets high in copper and saturated fats are

associated with increased risk of ADassociated with increased risk of AD Saturated fats increase cholesterolSaturated fats increase cholesterol Foods highest in copper content are beef Foods highest in copper content are beef

liver, oysters, molluscs, almonds, and liver, oysters, molluscs, almonds, and cocoacocoa

BRITISH JOURNAL OF NUTRITION; BRITISH JOURNAL OF NUTRITION; Loef,M;107:7 (2011)Loef,M;107:7 (2011)

20

Discussion Discussion

Tell your partner what you Tell your partner what you understood and think while your understood and think while your partner silently listens – talk for a partner silently listens – talk for a couple of minutescouple of minutes

Switch roles – partner that listened Switch roles – partner that listened becomes the speaker for a couple of becomes the speaker for a couple of minutesminutes

Short discussion Short discussion

21

NSAIDsNSAIDs Persons taking Persons taking NNon-on-SSteroidal teroidal AAnti-nti-IInflammatory nflammatory

DDrugs (rugs (NSAIDNSAIDs) for more than two years show a s) for more than two years show a 50% greater protection from AD than those not 50% greater protection from AD than those not taking NSAIDs. taking NSAIDs.

The same effect is not seen for cortisol, which has The same effect is not seen for cortisol, which has a more profound anti-inflammatory effect. a more profound anti-inflammatory effect. NEUROBIOLOGY OF AGING 22:799 (2001)NEUROBIOLOGY OF AGING 22:799 (2001)

Older NSAIDs block both COX-1 and COX-2 Older NSAIDs block both COX-1 and COX-2 enzymesenzymes

Newer NSAIDs block COX-2 (pain)Newer NSAIDs block COX-2 (pain) COX-1 inhibition can cause GI bleedingCOX-1 inhibition can cause GI bleeding Microglia express COX-1Microglia express COX-1 NSAIDs (ibuprofen & indomethicin) inhibit NSAIDs (ibuprofen & indomethicin) inhibit

cytokine activation of beta-secretase (reduce Aß cytokine activation of beta-secretase (reduce Aß formation)formation) JOURNAL OF NEUROSCIENCE;Sastre,M;23:9796 (2003)JOURNAL OF NEUROSCIENCE;Sastre,M;23:9796 (2003)

22

AChE InhibitorsAChE Inhibitors Most FDA drugs for AD inhibit the enzyme Most FDA drugs for AD inhibit the enzyme

AcetylCholineEsterase (AChE)AcetylCholineEsterase (AChE) Was assumed to work by prolonging the Was assumed to work by prolonging the

existence of acetylcholine in synapsesexistence of acetylcholine in synapses AChE promotes Aß aggregation, which AChE promotes Aß aggregation, which

inhibition may blockinhibition may block AChE inhibitors increase proportion of APP AChE inhibitors increase proportion of APP

cleaved by alpha-secretase rather than cleaved by alpha-secretase rather than beta-secretasebeta-secretase

AChE inhibitors cause nausea, vomiting and AChE inhibitors cause nausea, vomiting and diarrheadiarrhea

AChE inhibitors cause modest and transient AChE inhibitors cause modest and transient slowing of progress of ADslowing of progress of AD

23

MemantineMemantine Inflammation & oxidative stress can Inflammation & oxidative stress can

cause excessive glutamate release cause excessive glutamate release (excitotoxicity)(excitotoxicity)

Memantine protects against Memantine protects against excitotoxicity without interfering excitotoxicity without interfering with glutamate signallingwith glutamate signalling

Like AChE inhibitors, benefit of Like AChE inhibitors, benefit of memantine therapy for AD is, memantine therapy for AD is, although statistically significant, although statistically significant, nonetheless marginalnonetheless marginal

24

Nicotine and smokingNicotine and smoking Nicotine administered to transgenic mice reduced AßNicotine administered to transgenic mice reduced Aß42 42

plaquesplaques JOURNAL OF NEUROCHEMISTRY;81:655 (2002)JOURNAL OF NEUROCHEMISTRY;81:655 (2002)

Nicotine administered to the rat hippocampus enhanced Nicotine administered to the rat hippocampus enhanced acetylcholine production and releaseacetylcholine production and release BIOLOGICAL PSYCHIATRY;49:200 (2001)BIOLOGICAL PSYCHIATRY;49:200 (2001)

Transgenic mice show worsening of NFTs with nicotineTransgenic mice show worsening of NFTs with nicotine PNAS;102:3046 (2005)PNAS;102:3046 (2005)

Many studies show more twice the risk of AD among Many studies show more twice the risk of AD among smokerssmokers THE LANCET; 351:1840 (1998)THE LANCET; 351:1840 (1998) NEUROBIOLOGY OF AGING; 24:589 (2003)NEUROBIOLOGY OF AGING; 24:589 (2003) AMERICAN JOURNAL OF EPIDEMIOLOGY;166:367(2007)AMERICAN JOURNAL OF EPIDEMIOLOGY;166:367(2007)

Tobacco smoke contains more than just nicotineTobacco smoke contains more than just nicotine

25

Insulin and Insulin Insulin and Insulin sensitivitysensitivity Diabetics have greater risk for ADDiabetics have greater risk for AD Insulin increases Aß degradationInsulin increases Aß degradation Chromium picolinate (which increases Chromium picolinate (which increases

insulin sensitivity) improved memory insulin sensitivity) improved memory performance in patients with mild ADperformance in patients with mild AD NUTRITIONAL NEUROSCIENCE;13:116 (2010)NUTRITIONAL NEUROSCIENCE;13:116 (2010)

Similar benefits were seen with the insulin-Similar benefits were seen with the insulin-sensitizing drug metforminsensitizing drug metformin PNAS;Chen,Y;106:3907 (2009)PNAS;Chen,Y;106:3907 (2009)

26

Ginko bilobaGinko biloba A large randomized trial showed ginko A large randomized trial showed ginko

biloba improved cognition in AD patientsbiloba improved cognition in AD patients JOURNAL OF NEUROLOGICAL SCIENCES;283:224 (2009)JOURNAL OF NEUROLOGICAL SCIENCES;283:224 (2009)

A review of a large number of studies also A review of a large number of studies also showed ginko biloba improved cognition in showed ginko biloba improved cognition in AD patientsAD patients BMC GERIATRICS;10:14 (2010)BMC GERIATRICS;10:14 (2010)

A large 6-year randomized trial showed A large 6-year randomized trial showed ginko biloba is not effective in preventing ADginko biloba is not effective in preventing AD JOURNAL OF THE AMERICAN MEDICAL JOURNAL OF THE AMERICAN MEDICAL

ASSOCIATION;300:2253 (2008)ASSOCIATION;300:2253 (2008)

Does ginko biloba treat, but not prevent Does ginko biloba treat, but not prevent AD ?AD ?

27

Transgenic AD-prone Transgenic AD-prone rodentsrodents Transgenic rats with gene delivery of Brain-Transgenic rats with gene delivery of Brain-

Derived Neurotrophic Factor (BDNF) after disease Derived Neurotrophic Factor (BDNF) after disease onset reversed synapse loss and restored learning onset reversed synapse loss and restored learning and memory and memory NATURE MEDICINE;15:331 (2009)NATURE MEDICINE;15:331 (2009)

Glycogen-Synthase Kinase 3 (GSK-3), an enzyme Glycogen-Synthase Kinase 3 (GSK-3), an enzyme that phosphorylates tau protein, when inhibited by that phosphorylates tau protein, when inhibited by lithium in transgenic mice, substantially reduced lithium in transgenic mice, substantially reduced NFT formationNFT formation PNAS;102:6990 (2005)PNAS;102:6990 (2005)

Transgenic mice given pomegranate juice from 6 Transgenic mice given pomegranate juice from 6 to 12.5 months of age showed 50% less to 12.5 months of age showed 50% less accumulation of soluble Aß and amyloid deposits in accumulation of soluble Aß and amyloid deposits in the hippocampus associated with improved the hippocampus associated with improved learning and memory.learning and memory. NEUROBIOLOGY OF DISEASE; 24:506 (2006)NEUROBIOLOGY OF DISEASE; 24:506 (2006)

28

Cytokine antagonistCytokine antagonist Etanercept, an antagonist of the Etanercept, an antagonist of the

inflammatory cytokine Tumor inflammatory cytokine Tumor Necrosis Factor alpha (TNF−α) has Necrosis Factor alpha (TNF−α) has shown effectiveness in reducing shown effectiveness in reducing symptoms in an AD patient within symptoms in an AD patient within hours of administrationhours of administration JOURNAL OF NEUROINFLAMMATION;5:2 JOURNAL OF NEUROINFLAMMATION;5:2

(2008)(2008)

29

CurcuminCurcumin Curcumin is a phytochemical which gives Curcumin is a phytochemical which gives

curry a yellow colorcurry a yellow color Incidence of AD is substantially lower in Incidence of AD is substantially lower in

IndiaIndia Curcumin is an antioxidant that can scavenge Curcumin is an antioxidant that can scavenge

peroxynitriteperoxynitrite Curcumin not only inhibits Aß aggregation, it Curcumin not only inhibits Aß aggregation, it

disaggregates existing plaquesdisaggregates existing plaques Curcumin can lower insulin sensitivityCurcumin can lower insulin sensitivity Curcumin can lower the inflammatory Curcumin can lower the inflammatory

cytokine InterLeukin-1ß (IL-1ß) nearly 60% cytokine InterLeukin-1ß (IL-1ß) nearly 60% in transgenic micein transgenic mice

30

Low folate and elevated Low folate and elevated homocysteinehomocysteine Low serum folic acid and elevated plasma Low serum folic acid and elevated plasma

homocysteine are both independent risk factors homocysteine are both independent risk factors for AD for AD AMERICAN JOURNAL OF CLINICAL NUTRITION;82:636 AMERICAN JOURNAL OF CLINICAL NUTRITION;82:636

(2005)(2005)

Folic acid deficiency and excess homocysteine Folic acid deficiency and excess homocysteine impair DNA repair, sensitizing neurons to cell impair DNA repair, sensitizing neurons to cell death from DNA damagedeath from DNA damage JOURNAL OF NEUROSCIENCE;22:1752 (2002)JOURNAL OF NEUROSCIENCE;22:1752 (2002)

Folic acid deficiency and excess homocysteine Folic acid deficiency and excess homocysteine increase Aß production by inducing beta-increase Aß production by inducing beta-secretase – an effect that can be overcome by secretase – an effect that can be overcome by administering S-Adenosyl Methionine (SAMe)administering S-Adenosyl Methionine (SAMe) MOLECULAR AND CELLULAR NEUROSCIENCE;28:195 (2005)MOLECULAR AND CELLULAR NEUROSCIENCE;28:195 (2005)

31

ExerciseExercise A mouse model of AD showed reduced A mouse model of AD showed reduced

extracellular Aß with voluntary extracellular Aß with voluntary exercise exercise JOURNAL OF NEUROSCIENCE;25:4217 (2005)JOURNAL OF NEUROSCIENCE;25:4217 (2005)

A 14-year study showed a 29-50% A 14-year study showed a 29-50% reduction in AD with physical activityreduction in AD with physical activity JAMA; 302:627 (2009)JAMA; 302:627 (2009)

A randomized study of over 4,000 men A randomized study of over 4,000 men and women over age 65 showed and women over age 65 showed reduced AD with physical activityreduced AD with physical activity ARCHIVES OF NEUROLOGY;58:498 (2001)ARCHIVES OF NEUROLOGY;58:498 (2001)

32

StressStress Transgenic AD-prone mice show Transgenic AD-prone mice show

increased Aß accumulation, which is increased Aß accumulation, which is apparently corticosteroid-relatedapparently corticosteroid-related AMERICAN JOURNAL OF CLINICAL AMERICAN JOURNAL OF CLINICAL

NUTRITION;82:636 (2005)iNUTRITION;82:636 (2005)i Glucocorticoid cascade hypothesisGlucocorticoid cascade hypothesis

Cortisol (stress hormone) rises with ageCortisol (stress hormone) rises with age Damages hippocampus further increasing Damages hippocampus further increasing

cortisolcortisol Destructive feedback cycleDestructive feedback cycle Pacific salmon use corticosteroids to self-Pacific salmon use corticosteroids to self-

destructdestruct

33

Environmental enrichmentEnvironmental enrichment A study of transgenic AD-prone mice A study of transgenic AD-prone mice

showed that environmental enrichment showed that environmental enrichment worsened amyloid plaque formation worsened amyloid plaque formation JOURNAL OF NEUROPATHOLOGY AND JOURNAL OF NEUROPATHOLOGY AND

EXPERIMENTAL NEUROLOGY; 62:1220 (2003)EXPERIMENTAL NEUROLOGY; 62:1220 (2003)

A subsequent study claimed that the A subsequent study claimed that the former study had subjected the mice to former study had subjected the mice to excessive stress, and showed reduced excessive stress, and showed reduced Aß associated with environmental Aß associated with environmental enrichment enrichment CELL; 120:701 (2005)CELL; 120:701 (2005)

34

Discussion Discussion

Tell your partner what you Tell your partner what you understood and think while your understood and think while your partner silently listens – talk for a partner silently listens – talk for a couple of minutescouple of minutes

Switch roles – partner that listened Switch roles – partner that listened becomes the speaker for a couple of becomes the speaker for a couple of minutesminutes

Short discussion Short discussion

35

Empirical versus Empirical versus MechanisticMechanistic

Empirical treatment and preventionEmpirical treatment and prevention What appears to workWhat appears to work

Mechanistic treatment and preventionMechanistic treatment and prevention Understand the mechanismsUnderstand the mechanisms Devise strategies based on mechanismsDevise strategies based on mechanisms Evaluate what may work or not to Evaluate what may work or not to

understand the mechanisms and improve understand the mechanisms and improve strategies. strategies.

36

Amyloid and NFTs in ADAmyloid and NFTs in AD