Antioxidants and Aging: The Role of Glutathione
Presented by: Joanna Helm Masters of Clinical Nutrition Candidate Graduate Programs in Human Nutrition
74 years young, gonna keep on having fun
Buddy Guy
Learning Objectives
1. Describe the role glutathione plays as an antioxidant in the body
2. Identify the diseases of aging associated with glutathione deficiency 3. Explain the risks and benefits of glutathione supplementation in the elderly population
Balance
Free Radicals
Unpaired electron
Electron donation
Nucleus
Nucleus
Antioxidant
Free Radical
Free Radicals
Antioxidant System
Catalase Peroxidase
OH
Hydroxyl radical
OH-
Superoxide Dismutase
O O
Peroxide
-O2-2
VS
Glutatione Peroxidase (Gpx)
Glutathione Reductase
(Grx) Vitamin C Vitamin E
O O
Superoxide anion
.O
2 Sies 1997
LEO says GER
Lose Electron Oxidation Gain Electron Reduction
What are environmental sources of free radicals?
http://www.medicinaosteopatica.it/public/44_2.jpg
Free Radical Theory of Aging
Introduced in 1956 by Denham Harman, MD, PhD Proposed the concept of free radicals role in the aging process
Damage Accumulation Theories free radical theory glycation theory error catastrophe theory membrane theory entrophy theory Genetic Theories Programmed to a set life span
Harman, 1956
Damage begins with our first breath
Cadenas & Davies 2000, Valko 2007
Glutathione (GSH)
Are these essential or non essential amino acids?
Braganza, 2010
Absorption
Lumen or Blood
Glutathione
Glutamate
Amino acid transporter
Cytoplasm
Blood
Glutamate
Cysteine
Amino acid transporter
Cysteine
Glycine
Glycine
Amino acid transporter
Glutathione
Biochemistry
Reduced Glutathione (2 GSH)
NADP+
Hydrogen Peroxide H2O2
Riboflavin
Selenium GSH peroxidase
GSH reductase
Water
NADPH + H+
Oxidized Glutathione (GSSH)
Rebrin, 2008
What happens if your body does not make glutathione?
1. Liver would fail with no way to excrete pollutants, drugs, or toxic metals Cells die from due to the impact from free radical damage Immune system would be vulnerable to bacteria, viruses and disease
2.
3.
Board 2013, Valko 2007
Aging, Illness and Glutathione Depletion
LHP Lipid hydroperoxide GSH - Glutathione
8.51
8.84
Severity of illness
2.14
3.14
Oxidative markers (LHP)
0.54
Decrease in plasma glutathione Result = reduced ability to manage oxidative stress
p=.0001
0.29 0.24 0.17
Young, healthy
( 24.5 +/- 4.7 yrs)
Elderly, healthy
( 70.7 +/- 4.8 yrs)
Elderly, chronic
(75.7 +/- 8.3 yrs)
Elderly, inpatient
(77.2 +/- 8.6 yrs)
n=66
n=58
n=49
n=47
Nuttal, Lancet, 1998
Young vs Old Glutathione Concentrations
Mean (+/-SEM) glutathione concentrations in healthy young (n=8) and healthy elderly (n=8) subjects before and after supplementation with cysteine & glycine GSH deficiency in the elderly occurs due to diminished supply of precursors, not due to a diminished capacity to synthesize GSH. a
2.08
+/- 0.12
c b
1.12
+/- 0.18
94.6%
2.18
+/- 0.35
Young
Elderly presupplement
Elderly postsupplement
p<0.05 on the basis of 1 factor ANOVA and Bonferroni-corrected t-tests
a b C
Significantly different from elderly-pre supplementation (b) Significantly different from elderly-post supplementation (c) Not significantly different from young (a)
Sekhar 2011
Cataracts
Development of Cataracts
Presence of Free Radicals in lens
Wild type mice with Glutathione Peroxidase activity
Crystalline fibers in the lens cannot repair damaged proteins Accumulation of proteins at the center of the lens
Knock-out mice NO Glutathione Peroxidase activity
6 months = ~25-30 human years
Protein build up allows more UV light to enter the eye
Exacerbates the cycle of oxidative damage
Fan 2012
Cataracts
Impact of Glutathione Peroxidase deficiency on cataract formation in the mouse lens
GPX Knockout mice
50% had cataracts by 4 months of age
20% developed into nuclear cataracts by 9 months Every mouse had over 60% lens opacification where wild type mice had less than 20%
LEGSKO mice were genetically altered to not produce Glutathione Peroxidase. Slit-lamp images were taken periodically and lens opacity/cataract of any size were recorded for 9 months in homozygous LEGSKO mice vs. age matched wild type mice (n = 30 mice per group).
Fan 2012
Cancer therapies
1) Pro-drug is inactive when administered. 2) Taken into the cell and binds to glutathione (purple molecule). 3) Activation of the cytotoxic unit (orange), signals the oxidative stress pathway and apoptosis of the cancer cell. 4) Synergistic function with cancer cisplatins due to prodrug (blue) blocking the ability of the cisplatin to bind. (Cisplatin binding to glutathione creating drug resistance)
Telynta & Telcinta Currently in Phase II and Phase III clinical trials
Ortega 2011
N-acetyl cysteine (NAC)
Cysteine precursor Well absorbed in intestine No effect if GSH is within normal range Recommend 600 mg / day as supplement DO NOT supplement with nitroglycerin Easily purchased online, GNC, Vitamin Shoppe
Cost range: $14-$30/bottle, $0.02-$0.50/capsule
http://reference.medscape.com/drug/n-acetylcysteine-mucomyst-acetylcysteine-343425#90
Immune Deficiencies
N-acetylcysteine supplementation in postmenopausal women
* * *
* * * * *
*
*
n=18
n=18
n=18
n=18
n=18
n=18
Each column represents the mean +/- SE of duplicate assays *p< 0.01 Arranz, 2008
Cognition and Neurodegenerative Diseases
Excitatory amino acid transporter (EAAT) dysfunction
Cysteine uptake
Glutathione synthesis
Oxidative Stress Aging
Neurodegenerative Disease
Aoyama 2012; Currais, 2013; Pocernich 2012; Emir 2011; Huang 2010; Fu 2006
Young and at risk
Apo E 3/3 = lowest risk; n=21 Apo E 3/4 = intermediate risk; n=17 Apo E 4/4 = highest risk n=16
n= 25 age matched controls n= 58 with Alzheimers (AD)
*p<0.05
GCLC glutamylcysteine ligase GCLM glutamylcysteine ligase modifier GPx glutathione peroxidase Badia, 2013
*p<0.05 compared to Apo E 3/3
GSH synthesis
Values are means +/- SD
Dietary Friends of Glutathione
150 g of Glutathione from food Vitamin C Recommended supplement is 500 mg/day Methionine
Recommended supplement is 1600 mg/day
Selenium Copper B vitamins Zinc, Iron, Magnesium
Luschak 2012
DO NOT supplement L - CYSTEINE
Unsafe for routine oral administration Readily oxidizes to potentially toxic degradation products including hydroxyl radical Excitotoxin to the brain- similar to glutamate and aspartate
Toxic to the retina
Drug Interactions
Acetominophen depletes GSH
May cause liver failure in alcoholics
Ethacrynic acid diuretics, depletes GSH
Exubera- inhaled insulin action is
increased with NAC
Optimal Ratio of GSH:GSSG
Intracellular concentrations of GSH ranges from 0.1 15 /M Equilibrium between GSH and GSSG calculated using Nernst equation Highly controversial topic in Glutathione research
Compartment Cytosol Mitochondrial matrix Estimated pH 7.0 7.4 7.0 7.0 7.4 GSH:GSSG 3250:1 10-14:1 250:1 3:1 or 5:1 8:1
Mitochondrial inner membrane space
Endoplasmic Reticulum Plasma
Deponte, 2013
What labs can be used to measure oxidative stress?
Direct measure in red blood cells (RBCs)
GSH:GSSH ratio through enzyme assays and Nernst equation Fluorescent heme degradation products
Inflammatory markers IL-1, IL-6, TNF-alpha Lipids F2 Isoprostanes Protein carbonyls
Assays used in research to measure GSH
Gas chromatography-mass spectometry (GCMS) High pressure liquid chromatography (HPLC) ion exchange or fluorescence Trolox Equivalent Antioxidant Capacity Colorimetry Folin-Ciocalteu Reagent (FRC)
Clinical Pearls
Do they have a chronic condition? If so, how long have they been living with it? How balanced is their diet? What kind of medications are they taking? Are they over the age of 50? What other stressors do they have in their life? (Recent divorce, lost job, move, financial struggles, new baby, etc)
Thank you
Joanna Helm
helmj@ohsu.edu This presentation is available at www.harvestyourfood.com
