Oxidative stress and caloric
restriction
Jan Škrha
Professor of Medicine
3rd Department of Internal Medicine,
Laboratory for Endocrinology & Metabolism
1st Faculty of Medicine,
Charles University, Prague
IFCC Congress, Berlin 2011
OBESITY AND CONSEQUENCES
Overeating
Weight increase
Higher concentration of circulating FFA
Insulin resistance
Hyperinzulinemia
ROS
FFA – GENERATOR OF INSULIN RESISTANCE AND OXIDATIVE STRESS
FFA
Insulin
IRS-1 phosphoryl. serine/threonine
IRS-1 phosphoryl. tyrosine
FA-CoA
DAG
PKC
ROS
PI-3-kinase
NFĸB activation
GLUT 4 translocation
glucose transport
ROS
inflammatory proteins
Diabetes Care 27, 2004, 2253-9
SUPEROXIDE GENERATION IN MITOCHONDRIA
Respiratory chain
H+ gradient generation
H+
H+
Decrease of H+gradient
H+
H+
H+
UCP
Substrate
supply
III
I
Q-
e-
NAD+
II
e-
NADH
e-
IV
e-
Succinate
O2
Mn-SOD
O 2-
ATP
H2O
Fumarate
H2O+O2
cyt c
O2
ADP + P
UNIFYING MECHANISM FOR IMPAIRMENT
CAUSED BY HYPERGLYCEMIA AND FFA
FFA
Glucose
ROS
PARP
GAPDH
Polyols
AGE
Mitochondria
Nucleus
Cytoplasm
PKC
Hexosamine
NFκB
M.Brownlee, Diabetes 2005
ENDOTHELIAL CELL
Hyperglycemia
GLUT 1
Intracellular glucose
Reactive oxygen species in mitochondria
oxidative stress
polyols
glycation
PKCß
hexosamines
lipoxidation
glycoxidation
Endothelial dysfunction
DIABETIC ANGIOPATHY
EXOGENOUS AGE´s ACCELERATE OXIDATIVE STRESS
EXOGENOUS AGEs
NITROSATIVE STRESS
Endothelial dysfunction
MODULATION OF OXIDATIVE STRESS BY CALORIC INTAKE
REDUCED SUPEROXIDE GENERATION IN MITOCHONDRIA
Respiratory chain
H+ gradient generation
H+
H+
Decrease of H+gradient
H+
H+
H+
Decreased
substrate
supply
UCP
III
I
Q-
e-
NAD+
II
e-
NADH
cyt c
e-
IV
e-
Succinate
ATP
H2O
Fumarate
ADP + P
O2
Mn-SOD
H2O+O2
O 2-
O2
Gredilla et al., FASEB J 2001
Sirtuins – caloric restriction effectors
(silent information regulators – SIRT1-7)
family: NAD-dependent histone deacetylases
- influencing aging, metabolic processes, tumorigenesis
Reduced caloric intake:
SIRT1 upregulation
increases gluconeogenesis
decreases adipocyte formation
oposite to insulin
sirtuins like „molecular sensor“
Activators
• increase life span and cell survival
• promote fat mobilization
• increase the mitochondria number
Inhibitors
• stop tumor formation
• stop apoptosis
• stop neurodegenerative disease
Sirtuins – key regulators of oxidative stress
increase of antioxidative defense:
by upregulated MnSOD expression
by reduced cellular hydrogen peroxide
by enhanced mitochondrial glutathion capacity
reduced mitochondrial ROS production
Caloric restriction vs dietary composition
• reduced activity of complex I
vs complex III in mitochondria
• restriction of protein intake
(methionine content)
decreased ROS production
Crujeiras et al., Europ J Clin Invest 2008, Someya et al., Cell 2010, Sanz et al., J Bioenerg Biomembr 2004
Caloric restriction vs fasting
Caloric restriction and short
intermitent fasting
Prolonged fasting
beneficial effects:
harmful effects:
decreased ROS production
mitochondrial protection
superoxide anion release
from hepatocytes
decreased glutathione
content
Resistance to oxidative stress
increased
Mattson et al., J Nutr Biochem 2005
decreased
Sorensen et al., Free Radic Res 2006
BIOMARKERS
Biomarker
Caloric restriction
Lipid peroxidation
Malondialdehyde (MDA)
F-2-isoprostanes
decreased
decreased
Nitrosative stress
Nitrotyrosine
decreased
DNA damage
8-hydroxydeoxy-guanosine
decreased
Scavanger enzymes
SOD
CAT
GPx
GR
Non-enzymatic scavengers
GSH
Ascorbic acid
α-tocopherol
decreased, no change, increased
decreased, no change, increased
inverse relationship to CAT
GSH/GSSG ratio increased
no changes or increased
no changes (α-toc/chol+tg)
Cycling of OX/RED forms
Increased oxidative stress
Reduced oxidative stress
Comparison of the oxidative stress
measures by obese and nonobese
persons
3,5
1,6
3
1,4
MS
C
2,5
2
1,5
1
1
0,8
0,6
0,4
0,5
0,2
0
0
p<0,001
p<0,01
25
Glutathion (mmol/l)
MS
C
1,2
SOD (U)
MDA (mmol/l)
OXIDATIVE STRESS IN OBESE SUBJECTS
MS
C
20
15
10
5
0
p<0,01
OXIDATIVE STRESS IN OBESE SUBJECTS
25
90
80
MS
C
70
60
50
40
30
20
10
MS
C
20
15
10
5
0
0
p<0,01
p<0,01
2,5
a T/(CH+T) (mg/mmol)
a -Tocopherol (mg/l)
Ascorbic acid (m mol/l)
100
MS
C
2
1,5
1
0,5
0
p<0,01
OXIDATIVE STRESS IN OBESE SUBJECTS
10000
6
MS
C
CRP (mg/l)
5
4
3
2
log antiox LDL (mU/ml)
7
MS
C
100
1
1
0
p<0,05
p<0,05
DECREASED CALORIC INTAKE
(for obese or overweight individuals)
diabetic rats Wistar:
9 wks fed: group A – hypocaloric diet
group B – free diet
in group A: decreased TNF-α, IL-1, IL-4, IL-6
increased antiinflammatory mediators
and IL-10
Prevention of diabetic complications by supression
of inflammation due to decreased oxidative stress
Ugochukwu et al., J Nutr Biochem 2007, 18, 120-126
COMBINATION OF DIET AND PHYSICAL ACTIVITY
Improved lifestyle in 19 children with overweight
2 wks: diet with reduced fat + increased fiber contents
2hrs daily physical training
Results: decrease: cholesterol, TG, 8-iso-PGF-2,
ICAM-1, selectin, CRP, myeloperoxidase,
superoxide and H2O2
increase: NO
Improved parameters associated with atherosclerosis risk
Roberts CK et al., Atherosclerosis 191, 2007, 98-106
CALORIC RESTRICTION & OXIDATIVE
STRESS
Patients:
A/ obese Type 2 diabetic patients (n=9)
B/ obese non-diabetic patients (n=9)
Methods:
VLCD diet (600 kcal), 1 week
Laboratory methods:
FFA, ß-HB, MDA, SOD, ascorbic acid,
alpha-tocopherol, T-chol, HDL, LDL-chol., TG
CALORIC RESTRICTION & OXIDATIVE
STRESS
Diabetic pts: Age
55 (41-70) yrs.
DM duration
12 ± 5 r.
BMI
36.2 ± 1.6 kg/m2
HbA1c
10.2 ± 1.6 %
Controls:
Age
BMI
HbA1c
53 (35-69) r.
37 ± 2.1 kg/m2
5.5 ± 0.4 %
Low-calory diet
16
FPG (mmol/l)
14
12
10
Before
Day 8
8
6
4
2
0
Diabetic patients
0,001
Control
Control persons
pesons
LDL-chol (mmol/l)
Low-calory diet
4
3,5
3
2,5
2
1,5
1
0,5
0
Before
Day 8
Diabetic patients
Control persons
pesons
Control
0,05
0,001
HDL-chol (mmol/l)
Low-calory diet
1,6
1,4
1,2
1
0,8
0,6
0,4
0,2
0
Before
Day 8
Diabetic patients
Control persons
pesons
0,001
0,001
Triglycerides (mmol/l)
Low-calory diet
3
2,5
2
Before
Day 8
1,5
1
0,5
0
Diabetic patients
Control
Control persons
pesons
0,001
0,05
Low-calory diet
MDA (m mol/l)
3
2,5
2
Before
Day 8
1,5
1
0,5
0
Diabetic patients
Control
persons
Control pesons
0,01
Low-calory diet
1
SOD (U)
0,8
0,6
Before
Day 8
0,4
0,2
0
Diabetic patients
Controlpersons
pesons
Control
0,01
0,01
Ascorbic acid (m mol/l)
Low-calory diet
68
66
64
62
60
58
56
54
52
Before
Day 8
Diabetic patients
Control
Control persons
pesons
0,01
a T/(Ch+T) (mg/mmol)
Low-calory diet
1,85
1,8
1,75
1,7
Before
Day 8
1,65
1,6
1,55
1,5
Diabetic patients
0,05
Control pesons
CALORIC RESTRICTION & OXIDATIVE STRESS
Conclusions
1.
Caloric restriction lowers LDL and HDL-cholesterol
and triglycerides
2.
Significant decrease of oxidative stress was found in
obese non-diabetic pts (MDA decrease, SOD and
ascorbic acid increase), these changes were only
borderline in diabetic patients
3.
Obese diabetic patients are more resistant to low
calory diet in comparison with obese non-diabetic
patients and they reduce oxidative stress less than
non-diabetic persons
a) Oxidative stress is higher in
obese than in nonobese persons
b) Very low calory diet decreases
the level of oxidative stress
Thank you