Transcript oxidative stress

Illness suggested to be associated
with oxidative stress
Eye
Body
Brain
Air tube
Face
Chest
Abdomen
Lower abdomen
Radiation
UV radiation
Antioxidants
Vitamin E
Vitamin C
b-Carotene
Ubiquinone
Flavonoids
Scavenging
Activated
oxygen
Free radicals
Detergents
Smoking
Additives
Agricultural
chemicals
Air pollutants
Raspberry
Strawberry
Blackcurrant
ORAC=Oxygen Radical Absorbance Capacity
http://www.hsrmagazine.com/articles/2c1specialty2.html
“Antioxidants!
Antioxidants!….”
การใช้ ผลิตภัณฑ์ เสริมอาหารของผู้สูงอายุทรี่ ่ วมในกลุ่ม
the New Mexico Aging Process Study
50
42.18
Women
Men
40
30
20
26.77
20.09
11.72
10
0
20.08
14.42
16.06
45.62
41.16
18.71
27.97
20.9
1994 1995 1996 1997 1998 1999
ร้ อยละของการเกิดผลเสี ย
จากการใช้ ผลิตภัณฑ์ ฯ
(ปี ค.ศ.)
Year 1994 1995 1996 1997 1998 1999
%
11.9 19.7 13.2
24.1 29.3 30.6
Wold et al.,J Am Diet Assoc, 2005;105:54-63.
1.Generation of free radicals, oxidative stress
& their’s damaging effects: ศ.ดร.ไมตรี สุ ทธจิตต์
2.Antioxidants in metabolic
disorders: รศ.ดร.วีรพล คู่คงวิริยพันธ์
3.Antioxidants in neurodegenerative
disorders: รศ.ดร.จินตนา สั ตยาศัย
4.Antioxidants in cosmetics:
รศ.ดร.พรรณวิภา กฤษฏาพงศ์
รศ.ดร. จินตนา สั ตยาศัย
ภาควิชาเภสั ชวิทยา
คณะแพทยศาสตร์ มหาวิทยาลัยขอนแก่น
CNS
และ Oxidative
stress
•สมองมีปริมาณไขมันไม่ อมิ่ ตัว (PUFAs) เป็ นจานวนมากทาให้ ไว
ต่ อภาวะเครียดทางออกซิเดชัน
•สมองใช้ ออกซิเจนในอัตราทีส่ ู งมาก จึงมีการปล่อย oxidants
ออกจาก neural mitochondrial และสร้ าง superoxide anion ได้ มาก
•ปริมาณของ Antioxidant enzymes ใน extracellular space มีน้อย:
-SOD ใน neurons
-GSH และ GPX (peroxidases) ใน astrocytes
-activity ของ Catalase และ GSH-Px มีต่า
•Oxidative stress เกิดขึน้ ได้ โดยหลายกลไก เช่ น
-การเพิม่ intracellular free Ca2+
-การหลัง่ excitatory amino acids (Glutamate)***
(GSH=glutathione;GSH-Px=glutathione peroxidase)
Reactions important in the production and
defense from reactive species in neurons
H 2O + O 2
HO+O
Fe2+
+ O2
Fe3+
O2 + e-
2
O2
-.
H2O2
O2 + OH- + OH.
(Haber-Weiss
reaction)
NO.
ONOO-
SOD
NO2
+
.NO
2
GSSG
GSH-Px
GSH-Red
2
SOD
H 2O 2 + O 2
2H+
Fe2+/Cu+
OH. + OH- + Fe3+
(Fenton Reaction)
+ OH.
Nitration of
residue
tyrosine
GSH
RH (organic compound)
R. (organic radical)
O2
RO2 (peroxy radical)
GSH-Px = glutathione peroxidase; SOD=super oxide dismutase;
GSSH = glutathione disulfide; ONOO-=peroxynitrite;
GSH = glutathione; O2-.=superoxide species;
GSH-red = glutathione reductase; OH.=hydroxyl species
ลูกจ๋ า มากิน antioxidants เพือ่
จะได้ ลดการทาลายเซลล์ สมอง
ที่เกิดจาก oxidants ใน junk food
X
Junk Food
Antioxidant
menu
Nitric oxide (NO) as
-an intercellular messenger
-an atypical neurotransmitter
In neurotransmitter
release
mGluR-II,III
NMDA
Glu
NMDAR1/NMDAR2A
high Mg2+ sensitivity
-
AMPA
Ca2+
(basal negative feedback)
+ mGluR-I
+ mGluR-I
NO
High Ca2+
As neurotoxin
PAF-R
PAF
Ca2+ mediated signals
Long term potentiation
(LTP)
-การเรียนรู้ และความจา
-neuroplasticity, etc.
Hydrogen peroxide (H2O2)
H2O2, a membrane-permeable form of ROS,
normally produced in living cells and synapses.
H2O2 enhanced NMDA-dependent
LTP in hippocampus
Synaptic plasticity
Functions of brain plasticity
-Brain development
-Learning & memory
-Psychiatric disorders
-Neurological disorders
(Kamsler & Segal, 2003)
Renal graft
Degenerative retinal damage Glomerulonephritis
Cataractogenesis
Eye
Kidney
Ischemic bowel
Liver injury
Skin
Infarction
GI
OXIDATIVE STRESS
Vasospasm Vessels
Atherosclerosis
Burn
Dermatitis
Psoriasis
Heart
Rheumatoid
arthritis
Joints
Asthma
Lung
Aging Multi-organ
Hyperoxia
Brain
Cancer
Aging
DM
Trauma
Stroke
Parkinson’s disease (PD)
Huntington’s disease (HD)
Alzheimer’s disease (AD)
Amyotrophic lateral sclerosis (ALS)
Multiple sclerosis (MS)
Aging, Trauma & Stroke
Stroke Aging Other
factors
Reduction of blood flow (ischemia/hypoxia)
Depletion of energy stores
Na+-K+-pump failure
Acidosis
Membrane depolarization
Failure of Ca2+
Glutamate release buffering systems and pumps
Opening of voltageActivation of NMDA,AMPA
2+
sensitive Ca channels & metabotropic receptors
Reperfusion
Elevation of intracellular Ca2+ levels
NO production
Activation of NO
Free-radical
synthase,lipases,
Inflammation
formation
proteases and
endonuclease
Lipid peroxidation Release of cytokines
Apoptosis
Irreversible cell damage
CELL DEATH
(From Calabresi et al.,2003)
Parkinson’s Disease
Biochemical events associated with
neurodegeneration of DAneurons in PD
Glutamate excitotoxicity
Release of
ferritin iron
neurotoxins
Impaired cellular
respiration
Neuronal
death
Nitric oxide
Iron accumulation, oxidative
stress & inflammation
Protein
aggregation
Reduction in ubiquitinproteosome system
(Mandel et al., 2003)
Alzheimer’s Disease
Non amyloidogenic
pathway
g secretase
a secretase
Amyloidogenic
pathway g secretase
Ab
b secretase
Ab generation
Reactive Oxygen Species
Tau hyperOxidation Excito- Ab aggre-Inflam- phosphorylation
toxicity gation mation
Senile plaque withNeurofibrillary
microglial activation tangles
Cell
death
(Gamblin et al., 2000)
Cognitive
& behavioral
-Neurotransmitter
abnormalities
deficit,
-Loss of
neuroplasticity
Amyotrophic Lateral Sclerosis
Oxygen radical
Hydrogen
peroxide
Free Radical Damage to Motor Neurons
(Eisen, 2000)
Multiple Sclerosis
Environmental factors
Glutamate
Excitotoxicity
Demyelination
Genetic factors
ROS
production
Macrophage
Transcription factors
Gene upregulation (I.e., TNF-a)
Axonal damage
Oligodendrocyte and neuronal loss
Sources of ROS & cellular events in MS
(Gilgun-Sherki et al., 2004)
Cellular Pathogenesis in HD
•Antioxidant vitamins
•Plant polyphenols
•Human endogenous ligands
•Female sex hormone: Estrogen
& Phytoestrogens
Antioxidant vitamins
Ascorbic acid
(vit C)
Antioxidants
Neuroprotectants
•Both Vit C & E do not
reduce risk of dementia
or PD(CNS Drugs 2003;Cummings,
N Engl J Med 2004)
Alpha-tocopheral
(vit E)
Pro-oxidants
•Potentiate extrapyramidal
effects of haloperidol & NOS
inhibitors (Lazzarini et al., Psychopharmacol,
2005)
•Vit C: Hb denaturation in G-6
•Vit E but not Vit C
could have a role in ALS -PD def. (Papandreou & Rakitzis, 1990)
prevention: clinical trials
(Ascherio et al., Ann Neurol 2005)
•Vit E: antioxidative enzymes
in erythrocytes (Eder et al., 2002)
Vitamin A & beta-carotene
Antiamyloidogenic activity
(in cell culture) (Ono et al., Exp Neurol 2004)
Control: 0 h
Control: 6 h
+retinol: 6 h
Electronmicrograph
of fibril extension
retinol = retinal > beta-carotene > retinoic acid.
Vitamins B2, B6, C, and E at
50 and 100 μM
had no inhibitory effect
-Ginkgo biloba (EGb)
-Catechins
-Caffeic acid phenethyl ester
(from honeybee’s propolis)
Ginkgo biloba (EGb)
แปะก๊วย
Flavonoids
Free radical scavengers
Egb had small but significant effect in AD patients
(Cummings, N Engl J Med 2004)
Control
The expression of tyrosine
hydroxylase (DA neuron) in
substantia nigra of rat (PD model)
10 mg 6-OHDA
+50 mg/kg EGb
+100 mg/kg EGb
+150 mg/kg EGb
EGb=Gingko biloba extract
3 wks pretreatment
(Ahmad et al., J Neurochem, 2005)
•antioxidant
•free radical scavenging
•MAO-B inhibiting
•DA-enhancing mechanisms
Rescue the DA neurons
(PD model)
Camellia sinensis
Catechins
A group of flavonoids; ~30-45% of
the solid green tea extract
(-)-epigallocatechin-3-gallate (EGCG)
(-)-epigallocatechin (EGC)
(-)-epicatechin (EC)
(-)-epicatechin-3-gallate (ECG)
Infarc Size (mm3)
EGCG as an intervention
of cerebral ischemia
50mg/kg EGCG i.p., after ischemia;
rats were killed 72h post ischemia.
(Rahman et al., Neurosci Lett 2005)
~10%
Antioxidant prop.
EGCG=ECG>EGC>EC
EGCG: modulation of cell death gene
in Parkinson’s model
(Mandel& Youdim, Free Rad Biol Med 2004)
EGCG=potential candidate
for the treatment of
neurodegenerative disorders
Caffeic acid phenethyl ester
(CAPE)
Active antioxidant flavonoids (45-55%)
from honeybee propolis
Control
6-OHDA
6-OHDA
+ CAPE
Cultured cerebellar
granule neurons (CGN)
red fluorescent=death neuron
Effect of CAPE (mM) on
Ca2+-induced Cyt-C release
in rat liver mitochondria
Propolis = neuroprotectant; a good
candidate for in vivo models
(Noelker et al., Neurosci Lett 2005)
Biochemical Pharmacology 70 (2005) 220-228
Model for MS: oral flavonoids fail to
beneficially influence the course of EAE
in mice but, instead, suppress recovery
from acute inflammatory damage.
(flavonoids tested-apigenin, luteolin,
quercetin, hesperitin, morin,
fisetin & curcumin)
Human endogenous ligands
Coenzyme Q10 (ubiquinone)
=important antioxidant in both
mitochondria and lipid membrane
360mg/day: therapeutic effect in HD patients
(Korozhetz et al., Ann Neurol 1997)
Slow down functional decline in PD patients
(Frucht, CNS Drugs 2005)
Protect DA neuronal death from pesticide rotenone
(Moon et al., J Neurochem 2005)
Coenzyme Q10 has the potential
to be used as a therapeutic
intervention for neurodegenerative
diseases.
(Somayajulu et al., Neurobiol Dis 2005)
a-Lipoic acid (a-LA)
A biological antioxidant , cofactor in many
mitochondrial reactions
EAE= experimental autoimmune
encephalomyelitis; a model
for MS
a-LA=a potential therapy for MS
(mechanisms other than its
antioxidant activity)
(Morini et al., J Neuroimmunol 2004)
Melatonin
Natural compound of almost ubiquitous occurrence
AMK=Melatonin metabolite
(Hardeland & Pandi-Perumal, Nutr Met 2005)
Therapeutic trials with melatonin:
slowing the progression of AD but not of PD.
(Srinivasan et al., Neurotox Res 2005)
Melatonin protect hippocampus from the
effect of traumatic Brain Injury
CA1
CA3
DG
(Ozdemir et al.,Neurosci Lett 2005)
Female sex hormone: Estrogen
& Phytoestrogens
Antioxidant
effects
Estrogen receptors
(intracellular)
-ERa
-ERb
Neurotrophin Membrane Neurotransmitter
receptors
receptors binding sites
Modulation of
gene
transcription
Inhibition of
cell death
Interaction with
neurotrophin
signal transduction
pathways
Rapid non-genomic
intracellular
responses
Anti-inflammatory
activity
Modulation of
neurotransmitter
systems
Neurotrophic
effects
(Amantea et al., Pharmacol Res, 2005)
Rat’s brain: cognitive area
Estrogen
supplement
Estroge & Brain Plasticity
Estrogen supplement
increase dendritic knob
Control
Estrogen Replacement Therapy:
risk (uterine & breast cancer) VS benefit?
ERT
A brain selective estrogen
receptor modulator
(NeuroSERM) (Brinton, 2004)
A non-feminizing estrogen,
2-(1-adamantyl)-4methylestrone (ZYC-26)
(Perez et al., 2005)
Phytoestrogens=
natural SERMs
Pueraria mirifica (กวาวเครือ) :
isoflavonoids
Soy isoflavones:
Genistein, Daiazein,
Glycitein etc.
Soy isoflavone glycitein protects against betaamyloid
-induced toxicity and oxidative stress in transgenic
Caenorhabditis elegans.
Caenorhabditis elegans
(C. elegans)
Glycitein
Gutierrez-Zepeda et al., BMC Neurosci 2005
May have therapeutic potential
for prevention of Ab associated
neurodegenerative disorders
Antioxidant treatment for ALS
The Cochrane Library
2005, Issue 3
Main results
-No significant effect on the
primary outcome measure was
observed in a meta-analysis of
antioxidants in general when
combining the results.
-No significant differences
were demonstrated in secondary
outcome measures
Author’s conclusion
-While there is no substantial
clinical trial evidence to support
their clinical use, there is no clear
contraindication.
Antioxidant treatment for HD
Antioxidant efficacy was not observed
in human clinical trial. Studies have
been planned for other free-radical
scavengers. (Gardian & Veesei, J Neural Trans 2004)
Antioxidants and neurology
Clinical evidence that antioxidants agents
may prevent or slow the course of these
diseases is still relatively unsatisfactory,
and unsufficient to strongly modify
the clinical practice.
(Casetta et al., Curr Pharm Des. 2005)
Neuronal Cell Death
Normal neurons
Damaged neurons
Oxidants & Neurodegenerative disorders
Free radicals
Oxidative metabolism
cellular defence mechanism
-enzymes: SOD, Catalase
-others: vit.C, vit.E
MAO-B
-(PD) DA
DOPAC
.OH + OH-
-Inflammation
(MS)
Excitotoxicity
(Trauma, Stroke, Aging)
mismatch
Genetic defect:
e.g. Mutation of
SOD1 & ALS
Oxidative stress
Abnormal proteins
Mitochondrial dysfunction
-Alzheimer’s disease & b amyloid
& cell damage
-Prion protein & Prion disease (Mad cow)
Energy deprivation
& Cell death
EGCG polyphenols
VDAC=Voltage dependent anion channel
ANT=Adenosine nucleotide translocase
PBR=Peripheral benzodiazepine receptor
CK=Creatinine kinase
CyD=Cyclophilin D
Suggested potential targets of EGCG
Radical scavenging Green Tea Polyphenols
Iron chelation
?
Increasing antioxidant defense
(Mandel & Youdim,
Free Rad Biol Med 2004;
Weinreb et al., J Nutr
Biochem 2004))
Neurotoxin-induced X
ROS
Apoptotic genes
?
PKC
ANT
VDAC
sAPPa
Ab fibrils
NEUROPROTECTION
COMT